Merge pull request #6955 from livarcocc/fallback_folder_in_dotnet_hive

Move the NuGet fallback folder into the dotnet hive

packaging/deb/postinst

@@ -2,7 +2,7 @@
 echo "This software may collect information about you and your use of the software, and send that to Microsoft."
 echo "Please visit http://aka.ms/dotnet-cli-eula for more information."
 
-# Run 'dotnet new' as the user to trigger the first time experience to initialize the cache
+# Run 'dotnet new' to trigger the first time experience to initialize the cache
 echo "Welcome to .NET Core!
 ---------------------
 Learn more about .NET Core @ https://aka.ms/dotnet-docs. Use dotnet --help to see available commands or go to https://aka.ms/dotnet-cli-docs.
@@ -15,4 +15,4 @@ The data collected is anonymous and will be published in an aggregated form for
 
 The .NET Core Tools telemetry feature is enabled by default. You can opt-out of the telemetry feature by setting an environment variable DOTNET_CLI_TELEMETRY_OPTOUT (for example, 'export' on macOS/Linux, 'set' on Windows) to true (for example, 'true', 1). You can read more about .NET Core tools telemetry at https://aka.ms/dotnet-cli-telemetry."
 
-su - $SUDO_USER -c "dotnet new > /dev/null 2>&1 || true"
+dotnet new > /dev/null 2>&1 || true

packaging/osx/clisdk/scripts/postinstall

@@ -11,8 +11,7 @@ INSTALL_DESTINATION=$2
 # A temporary fix for the permissions issue(s)
 chmod -R 755 $INSTALL_DESTINATION
 
-# Run 'dotnet new' as user to trigger the first time experience to initialize the cache
+# Run 'dotnet new' to trigger the first time experience to initialize the cache
-INSTALLER_USER=$(stat -f '%Su' $HOME)
+$INSTALL_DESTINATION/dotnet new > /dev/null 2>&1 || true
-su - $INSTALLER_USER -c "$INSTALL_DESTINATION/dotnet new > /dev/null 2>&1 || true"
 
 exit 0

packaging/rpm/scripts/after_install_host.sh

@@ -19,4 +19,4 @@ The data collected is anonymous and will be published in an aggregated form for
 
 The .NET Core Tools telemetry feature is enabled by default. You can opt-out of the telemetry feature by setting an environment variable DOTNET_CLI_TELEMETRY_OPTOUT (for example, 'export' on macOS/Linux, 'set' on Windows) to true (for example, 'true', 1). You can read more about .NET Core tools telemetry at https://aka.ms/dotnet-cli-telemetry."
 
-su - $SUDO_USER -c "dotnet new > /dev/null 2>&1 || true"
+dotnet new > /dev/null 2>&1 || true

src/Microsoft.DotNet.Configurer/CliFallbackFolderPathCalculator.cs

@@ -12,14 +12,18 @@ namespace Microsoft.DotNet.Configurer
 {
     public class CliFallbackFolderPathCalculator
     {
-        public string CliFallbackFolderPath
+        public string CliFallbackFolderPath =>
+            Environment.GetEnvironmentVariable("DOTNET_CLI_TEST_FALLBACKFOLDER") ??
+            Path.Combine(new DirectoryInfo(AppContext.BaseDirectory).Parent.FullName, "NuGetFallbackFolder");
+
+        public string DotnetUserProfileFolderPath
         {
             get
             {
                 string profileDir = Environment.GetEnvironmentVariable(
                     RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? "USERPROFILE" : "HOME");
 
-                return Path.Combine(profileDir, ".dotnet", "NuGetFallbackFolder");
+                return Path.Combine(profileDir, ".dotnet");
             }
         }
 

src/Microsoft.DotNet.Configurer/DotnetFirstTimeUseConfigurer.cs

@@ -14,19 +14,22 @@ namespace Microsoft.DotNet.Configurer
         private INuGetCachePrimer _nugetCachePrimer;
         private INuGetCacheSentinel _nugetCacheSentinel;
         private IFirstTimeUseNoticeSentinel _firstTimeUseNoticeSentinel;
+        private string _cliFallbackFolderPath;
 
         public DotnetFirstTimeUseConfigurer(
             INuGetCachePrimer nugetCachePrimer,
             INuGetCacheSentinel nugetCacheSentinel,
             IFirstTimeUseNoticeSentinel firstTimeUseNoticeSentinel,
             IEnvironmentProvider environmentProvider,
-            IReporter reporter)
+            IReporter reporter,
+            string cliFallbackFolderPath)
         {
             _nugetCachePrimer = nugetCachePrimer;
             _nugetCacheSentinel = nugetCacheSentinel;
             _firstTimeUseNoticeSentinel = firstTimeUseNoticeSentinel;
             _environmentProvider = environmentProvider;
             _reporter = reporter;
+            _cliFallbackFolderPath = cliFallbackFolderPath;
         }
 
         public void Configure()
@@ -38,7 +41,13 @@ namespace Microsoft.DotNet.Configurer
 
             if (ShouldPrimeNugetCache())
             {
+                if (_nugetCacheSentinel.UnauthorizedAccess)
+                {
+                    PrintUnauthorizedAccessMessage();
+                }
+
                 PrintNugetCachePrimeMessage();
+
                 _nugetCachePrimer.PrimeCache();
             }
         }
@@ -55,14 +64,20 @@ namespace Microsoft.DotNet.Configurer
 
         private void PrintFirstTimeUseNotice()
         {
-            string firstTimeUseWelcomeMessage = LocalizableStrings.FirstTimeWelcomeMessage;
-
             _reporter.WriteLine();
-            _reporter.WriteLine(firstTimeUseWelcomeMessage);
+            _reporter.WriteLine(LocalizableStrings.FirstTimeWelcomeMessage);
 
             _firstTimeUseNoticeSentinel.CreateIfNotExists();
         }
 
+        private void PrintUnauthorizedAccessMessage()
+        {
+            _reporter.WriteLine();
+            _reporter.WriteLine(string.Format(
+                LocalizableStrings.UnauthorizedAccessMessage,
+                _cliFallbackFolderPath));
+        }
+
         private bool ShouldPrimeNugetCache()
         {
             return ShouldRunFirstRunExperience() &&

src/Microsoft.DotNet.Configurer/FirstTimeUseNoticeSentinel.cs

@@ -14,19 +14,19 @@ namespace Microsoft.DotNet.Configurer
 
         private readonly IFile _file;
 
-        private string _nugetCachePath;
+        private string _dotnetUserProfileFolderPath;
 
-        private string SentinelPath => Path.Combine(_nugetCachePath, SENTINEL);
+        private string SentinelPath => Path.Combine(_dotnetUserProfileFolderPath, SENTINEL);
 
         public FirstTimeUseNoticeSentinel(CliFallbackFolderPathCalculator cliFallbackFolderPathCalculator) :
-            this(cliFallbackFolderPathCalculator.CliFallbackFolderPath, FileSystemWrapper.Default.File)
+            this(cliFallbackFolderPathCalculator.DotnetUserProfileFolderPath, FileSystemWrapper.Default.File)
         {
         }
 
-        internal FirstTimeUseNoticeSentinel(string nugetCachePath, IFile file)
+        internal FirstTimeUseNoticeSentinel(string dotnetUserProfileFolderPath, IFile file)
         {
             _file = file;
-            _nugetCachePath = nugetCachePath;
+            _dotnetUserProfileFolderPath = dotnetUserProfileFolderPath;
         }
 
         public bool Exists()

src/Microsoft.DotNet.Configurer/INuGetCacheSentinel.cs

@@ -12,5 +12,7 @@ namespace Microsoft.DotNet.Configurer
         bool Exists();
 
         void CreateIfNotExists();
+
+        bool UnauthorizedAccess { get; }
     }
 }

src/Microsoft.DotNet.Configurer/INuGetConfig.cs

@@ -1,10 +0,0 @@
-// Copyright (c) .NET Foundation and contributors. All rights reserved.
-// Licensed under the MIT license. See LICENSE file in the project root for full license information.
-
-namespace Microsoft.DotNet.Configurer
-{
-    public interface INuGetConfig
-    {
-        void AddCliFallbackFolder(string fallbackFolderPath);
-    }
-}

src/Microsoft.DotNet.Configurer/LocalizableStrings.resx

@@ -136,4 +136,14 @@ A command is running to initially populate your local package cache, to improve
   <data name="FailedToPrimeCacheError" xml:space="preserve">
     <value>Failed to prime the NuGet cache. {0} failed with: {1}</value>
   </data>
+  <data name="UnauthorizedAccessMessage"  xml:space="preserve">
+    <value>Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </value>
+  </data>
 </root>

src/Microsoft.DotNet.Configurer/NuGetCachePrimer.cs

@@ -17,18 +17,14 @@ namespace Microsoft.DotNet.Configurer
 
         private readonly INuGetCacheSentinel _nuGetCacheSentinel;
 
-        private readonly INuGetConfig _nuGetConfig;
-
         private readonly CliFallbackFolderPathCalculator _cliFallbackFolderPathCalculator;
 
         public NuGetCachePrimer(
             INuGetPackagesArchiver nugetPackagesArchiver,
             INuGetCacheSentinel nuGetCacheSentinel,
-            INuGetConfig nuGetConfig,
             CliFallbackFolderPathCalculator cliFallbackFolderPathCalculator)
             : this(nugetPackagesArchiver,
                 nuGetCacheSentinel,
-                nuGetConfig,
                 cliFallbackFolderPathCalculator,
                 FileSystemWrapper.Default.File)
         {
@@ -37,7 +33,6 @@ namespace Microsoft.DotNet.Configurer
         internal NuGetCachePrimer(
             INuGetPackagesArchiver nugetPackagesArchiver,
             INuGetCacheSentinel nuGetCacheSentinel,
-            INuGetConfig nuGetConfig,
             CliFallbackFolderPathCalculator cliFallbackFolderPathCalculator,
             IFile file)
         {
@@ -45,8 +40,6 @@ namespace Microsoft.DotNet.Configurer
 
             _nuGetCacheSentinel = nuGetCacheSentinel;
 
-            _nuGetConfig = nuGetConfig;
-
             _cliFallbackFolderPathCalculator = cliFallbackFolderPathCalculator;
 
             _file = file;
@@ -61,8 +54,6 @@ namespace Microsoft.DotNet.Configurer
 
             var nuGetFallbackFolder = _cliFallbackFolderPathCalculator.CliFallbackFolderPath;
 
-            _nuGetConfig.AddCliFallbackFolder(nuGetFallbackFolder);
-
             _nugetPackagesArchiver.ExtractArchive(nuGetFallbackFolder);
 
             _nuGetCacheSentinel.CreateIfNotExists();

src/Microsoft.DotNet.Configurer/NuGetCacheSentinel.cs

@@ -1,6 +1,7 @@
 // Copyright (c) .NET Foundation and contributors. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
+using System;
 using System.IO;
 using Microsoft.DotNet.Cli.Utils;
 using Microsoft.Extensions.EnvironmentAbstractions;
@@ -13,8 +14,12 @@ namespace Microsoft.DotNet.Configurer
         public static readonly string SENTINEL = $"{Product.Version}.dotnetSentinel";
         public static readonly string INPROGRESS_SENTINEL = $"{Product.Version}.inprogress.dotnetSentinel";
 
+        public bool UnauthorizedAccess { get; private set; }
+
         private readonly IFile _file;
 
+        private readonly IDirectory _directory;
+
         private string _nugetCachePath;
 
         private string SentinelPath => Path.Combine(_nugetCachePath, SENTINEL);
@@ -23,14 +28,17 @@ namespace Microsoft.DotNet.Configurer
         private Stream InProgressSentinel { get; set; }
 
         public NuGetCacheSentinel(CliFallbackFolderPathCalculator cliFallbackFolderPathCalculator) :
-            this(cliFallbackFolderPathCalculator.CliFallbackFolderPath, FileSystemWrapper.Default.File)
+            this(cliFallbackFolderPathCalculator.CliFallbackFolderPath,
+                 FileSystemWrapper.Default.File,
+                 FileSystemWrapper.Default.Directory)
         {
         }
 
-        internal NuGetCacheSentinel(string nugetCachePath, IFile file)
+        internal NuGetCacheSentinel(string nugetCachePath, IFile file, IDirectory directory)
         {
-            _file = file;
             _nugetCachePath = nugetCachePath;
+            _file = file;
+            _directory = directory;
 
             SetInProgressSentinel();
         }
@@ -62,9 +70,9 @@ namespace Microsoft.DotNet.Configurer
         {
             try
             {
-                if (!Directory.Exists(_nugetCachePath))
+                if (!_directory.Exists(_nugetCachePath))
                 {
-                    Directory.CreateDirectory(_nugetCachePath);
+                    _directory.CreateDirectory(_nugetCachePath);
                 }
 
                 // open an exclusive handle to the in-progress sentinel and mark it for delete on close.
@@ -80,6 +88,10 @@ namespace Microsoft.DotNet.Configurer
                     1,
                     FileOptions.DeleteOnClose);
             }
+            catch (UnauthorizedAccessException)
+            {
+                UnauthorizedAccess = true;
+            }
             catch { }
         }
 

src/Microsoft.DotNet.Configurer/NuGetConfig.cs

@@ -1,39 +0,0 @@
-// Copyright (c) .NET Foundation and contributors. All rights reserved.
-// Licensed under the MIT license. See LICENSE file in the project root for full license information.
-
-using NuGet.Common;
-using NuGet.Configuration;
-using System.Linq;
-
-namespace Microsoft.DotNet.Configurer
-{
-    public class NuGetConfig : INuGetConfig
-    {
-        public const string FallbackPackageFolders = "packageSources";
-
-        private ISettings _settings;
-
-        public NuGetConfig(CliFallbackFolderPathCalculator cliFallbackFolderPathCalculator)
-        {
-            _settings = new Settings(cliFallbackFolderPathCalculator.NuGetUserSettingsDirectory);
-        }
-
-        internal NuGetConfig(ISettings settings)
-        {
-            _settings = settings;
-        }
-
-        public void AddCliFallbackFolder(string fallbackFolderPath)
-        {
-            if (!IsCliFallbackFolderSet(fallbackFolderPath))
-            {
-                _settings.SetValue(FallbackPackageFolders, "CliFallbackFolder", fallbackFolderPath);
-            }
-        }
-
-        private bool IsCliFallbackFolderSet(string fallbackFolderPath)
-        {
-            return _settings.GetSettingValues(FallbackPackageFolders).Any(s => s.Value == fallbackFolderPath);
-        }
-    }
-}

src/Microsoft.DotNet.Configurer/xlf/LocalizableStrings.cs.xlf

@@ -41,6 +41,25 @@ A command is running to initially populate your local package cache, to improve
 A command is running to initially populate your local package cache, to improve restore speed and enable offline access. This command will take up to a minute to complete and will only happen once.</target>
         <note />
       </trans-unit>
+      <trans-unit id="UnauthorizedAccessMessage">
+        <source>Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </source>
+        <target state="new">Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>

src/Microsoft.DotNet.Configurer/xlf/LocalizableStrings.de.xlf

@@ -41,6 +41,25 @@ A command is running to initially populate your local package cache, to improve
 A command is running to initially populate your local package cache, to improve restore speed and enable offline access. This command will take up to a minute to complete and will only happen once.</target>
         <note />
       </trans-unit>
+      <trans-unit id="UnauthorizedAccessMessage">
+        <source>Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </source>
+        <target state="new">Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>

src/Microsoft.DotNet.Configurer/xlf/LocalizableStrings.es.xlf

@@ -41,6 +41,25 @@ A command is running to initially populate your local package cache, to improve
 A command is running to initially populate your local package cache, to improve restore speed and enable offline access. This command will take up to a minute to complete and will only happen once.</target>
         <note />
       </trans-unit>
+      <trans-unit id="UnauthorizedAccessMessage">
+        <source>Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </source>
+        <target state="new">Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>

src/Microsoft.DotNet.Configurer/xlf/LocalizableStrings.fr.xlf

@@ -41,6 +41,25 @@ A command is running to initially populate your local package cache, to improve
 A command is running to initially populate your local package cache, to improve restore speed and enable offline access. This command will take up to a minute to complete and will only happen once.</target>
         <note />
       </trans-unit>
+      <trans-unit id="UnauthorizedAccessMessage">
+        <source>Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </source>
+        <target state="new">Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>

src/Microsoft.DotNet.Configurer/xlf/LocalizableStrings.it.xlf

@@ -41,6 +41,25 @@ A command is running to initially populate your local package cache, to improve
 A command is running to initially populate your local package cache, to improve restore speed and enable offline access. This command will take up to a minute to complete and will only happen once.</target>
         <note />
       </trans-unit>
+      <trans-unit id="UnauthorizedAccessMessage">
+        <source>Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </source>
+        <target state="new">Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>

src/Microsoft.DotNet.Configurer/xlf/LocalizableStrings.ja.xlf

@@ -41,6 +41,25 @@ A command is running to initially populate your local package cache, to improve
 A command is running to initially populate your local package cache, to improve restore speed and enable offline access. This command will take up to a minute to complete and will only happen once.</target>
         <note />
       </trans-unit>
+      <trans-unit id="UnauthorizedAccessMessage">
+        <source>Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </source>
+        <target state="new">Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>

src/Microsoft.DotNet.Configurer/xlf/LocalizableStrings.ko.xlf

@@ -41,6 +41,25 @@ A command is running to initially populate your local package cache, to improve
 A command is running to initially populate your local package cache, to improve restore speed and enable offline access. This command will take up to a minute to complete and will only happen once.</target>
         <note />
       </trans-unit>
+      <trans-unit id="UnauthorizedAccessMessage">
+        <source>Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </source>
+        <target state="new">Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>

src/Microsoft.DotNet.Configurer/xlf/LocalizableStrings.pl.xlf

@@ -41,6 +41,25 @@ A command is running to initially populate your local package cache, to improve
 A command is running to initially populate your local package cache, to improve restore speed and enable offline access. This command will take up to a minute to complete and will only happen once.</target>
         <note />
       </trans-unit>
+      <trans-unit id="UnauthorizedAccessMessage">
+        <source>Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </source>
+        <target state="new">Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>

src/Microsoft.DotNet.Configurer/xlf/LocalizableStrings.pt-BR.xlf

@@ -41,6 +41,25 @@ A command is running to initially populate your local package cache, to improve
 A command is running to initially populate your local package cache, to improve restore speed and enable offline access. This command will take up to a minute to complete and will only happen once.</target>
         <note />
       </trans-unit>
+      <trans-unit id="UnauthorizedAccessMessage">
+        <source>Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </source>
+        <target state="new">Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>

src/Microsoft.DotNet.Configurer/xlf/LocalizableStrings.ru.xlf

@@ -41,6 +41,25 @@ A command is running to initially populate your local package cache, to improve
 A command is running to initially populate your local package cache, to improve restore speed and enable offline access. This command will take up to a minute to complete and will only happen once.</target>
         <note />
       </trans-unit>
+      <trans-unit id="UnauthorizedAccessMessage">
+        <source>Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </source>
+        <target state="new">Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>

src/Microsoft.DotNet.Configurer/xlf/LocalizableStrings.tr.xlf

@@ -41,6 +41,25 @@ A command is running to initially populate your local package cache, to improve
 A command is running to initially populate your local package cache, to improve restore speed and enable offline access. This command will take up to a minute to complete and will only happen once.</target>
         <note />
       </trans-unit>
+      <trans-unit id="UnauthorizedAccessMessage">
+        <source>Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </source>
+        <target state="new">Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>

src/Microsoft.DotNet.Configurer/xlf/LocalizableStrings.zh-Hans.xlf

@@ -41,6 +41,25 @@ A command is running to initially populate your local package cache, to improve
 A command is running to initially populate your local package cache, to improve restore speed and enable offline access. This command will take up to a minute to complete and will only happen once.</target>
         <note />
       </trans-unit>
+      <trans-unit id="UnauthorizedAccessMessage">
+        <source>Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </source>
+        <target state="new">Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>

src/Microsoft.DotNet.Configurer/xlf/LocalizableStrings.zh-Hant.xlf

@@ -41,6 +41,25 @@ A command is running to initially populate your local package cache, to improve
 A command is running to initially populate your local package cache, to improve restore speed and enable offline access. This command will take up to a minute to complete and will only happen once.</target>
         <note />
       </trans-unit>
+      <trans-unit id="UnauthorizedAccessMessage">
+        <source>Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </source>
+        <target state="new">Permission denied to modify the '{0}' folder.
+
+Here are some options to fix this error:
+---------------------
+1. Re-run this command with elevated access.
+2. Disabled the first run experience by setting the environment variable DOTNET_SKIP_FIRST_TIME_EXPERIENCE to true.
+3. Copy the .NET Core SDK to a non-protected location and use it from there.
+    </target>
+        <note />
+      </trans-unit>
     </body>
   </file>
 </xliff>

src/Microsoft.DotNet.InternalAbstractions/DirectoryWrapper.cs

@@ -42,5 +42,10 @@ namespace Microsoft.Extensions.EnvironmentAbstractions
 
             return directoryFullName;
         }
+
+        public void CreateDirectory(string path)
+        {
+            Directory.CreateDirectory(path);
+        }
     }
 }

src/Microsoft.DotNet.InternalAbstractions/IDirectory.cs

@@ -14,5 +14,7 @@ namespace Microsoft.Extensions.EnvironmentAbstractions
         IEnumerable<string> GetFiles(string path, string searchPattern);
 
         string GetDirectoryFullName(string path);
+
+        void CreateDirectory(string path);
     }
 }

src/dotnet/Program.cs

@@ -128,7 +128,7 @@ namespace Microsoft.DotNet.Cli
 
                 if (telemetryClient == null)
                 {
-                    telemetryClient = new Telemetry(nugetCacheSentinel);
+                    telemetryClient = new Telemetry(firstTimeUseNoticeSentinel);
                 }
             }
 
@@ -177,18 +177,17 @@ namespace Microsoft.DotNet.Cli
                 var nugetPackagesArchiver = new NuGetPackagesArchiver();
                 var environmentProvider = new EnvironmentProvider();
                 var commandFactory = new DotNetCommandFactory(alwaysRunOutOfProc: true);
-                var nugetConfig = new NuGetConfig(cliFallbackFolderPathCalculator);
                 var nugetCachePrimer = new NuGetCachePrimer(
                     nugetPackagesArchiver,
                     nugetCacheSentinel,
-                    nugetConfig,
                     cliFallbackFolderPathCalculator);
                 var dotnetConfigurer = new DotnetFirstTimeUseConfigurer(
                     nugetCachePrimer,
                     nugetCacheSentinel,
                     firstTimeUseNoticeSentinel,
                     environmentProvider,
-                    Reporter.Output);
+                    Reporter.Output,
+                    cliFallbackFolderPathCalculator.CliFallbackFolderPath);
 
                 dotnetConfigurer.Configure();
             }

src/dotnet/Telemetry.cs

@@ -35,9 +35,9 @@ namespace Microsoft.DotNet.Cli
 
         public Telemetry () : this(null) { }
 
-        public Telemetry(INuGetCacheSentinel sentinel) : this(sentinel, null) { }
+        public Telemetry(IFirstTimeUseNoticeSentinel sentinel) : this(sentinel, null) { }
 
-        public Telemetry(INuGetCacheSentinel sentinel, string sessionId)
+        public Telemetry(IFirstTimeUseNoticeSentinel sentinel, string sessionId)
         {
             Enabled = !Env.GetEnvironmentVariableAsBool(TelemetryOptout) && PermissionExists(sentinel);
 
@@ -53,7 +53,7 @@ namespace Microsoft.DotNet.Cli
             _trackEventTask = Task.Factory.StartNew(() => InitializeTelemetry());
         }
 
-        private bool PermissionExists(INuGetCacheSentinel sentinel)
+        private bool PermissionExists(IFirstTimeUseNoticeSentinel sentinel)
         {
             if (sentinel == null)
             {

src/dotnet/commands/dotnet-msbuild/MSBuildLogger.cs

@@ -11,7 +11,8 @@ namespace Microsoft.DotNet.Tools.MSBuild
 {
     public sealed class MSBuildLogger : Logger
     {
-        private readonly INuGetCacheSentinel _sentinel = new NuGetCacheSentinel(new CliFallbackFolderPathCalculator());
+        private readonly IFirstTimeUseNoticeSentinel _sentinel =
+            new FirstTimeUseNoticeSentinel(new CliFallbackFolderPathCalculator());
         private readonly ITelemetry _telemetry;
 
         public MSBuildLogger()

src/dotnet/commands/dotnet-new/NewCommandShim.cs

@@ -28,8 +28,10 @@ namespace Microsoft.DotNet.Tools.New
 
         public static int Run(string[] args)
         {
-            var sessionId = Environment.GetEnvironmentVariable(MSBuildForwardingApp.TelemetrySessionIdEnvironmentVariableName);
+            var sessionId =
-            var telemetry = new Telemetry(new NuGetCacheSentinel(new CliFallbackFolderPathCalculator()), sessionId);
+                Environment.GetEnvironmentVariable(MSBuildForwardingApp.TelemetrySessionIdEnvironmentVariableName);
+            var telemetry =
+                new Telemetry(new FirstTimeUseNoticeSentinel(new CliFallbackFolderPathCalculator()), sessionId);
             var logger = new TelemetryLogger(null);
 
             if (telemetry.Enabled)

test/Microsoft.DotNet.Configurer.UnitTests/GivenADotnetFirstTimeUseConfigurer.cs

@@ -13,6 +13,8 @@ namespace Microsoft.DotNet.Configurer.UnitTests
 {
     public class GivenADotnetFirstTimeUseConfigurer
     {
+        private const string CliFallbackFolderPath = "some path";
+
         private Mock<INuGetCachePrimer> _nugetCachePrimerMock;
         private Mock<INuGetCacheSentinel> _nugetCacheSentinelMock;
         private Mock<IFirstTimeUseNoticeSentinel> _firstTimeUseNoticeSentinelMock;
@@ -45,7 +47,8 @@ namespace Microsoft.DotNet.Configurer.UnitTests
                 _nugetCacheSentinelMock.Object,
                 _firstTimeUseNoticeSentinelMock.Object,
                 _environmentProviderMock.Object,
-                _reporterMock.Object);
+                _reporterMock.Object,
+                CliFallbackFolderPath);
 
             dotnetFirstTimeUseConfigurer.Configure();
 
@@ -66,7 +69,8 @@ namespace Microsoft.DotNet.Configurer.UnitTests
                 _nugetCacheSentinelMock.Object,
                 _firstTimeUseNoticeSentinelMock.Object,
                 _environmentProviderMock.Object,
-                _reporterMock.Object);
+                _reporterMock.Object,
+                CliFallbackFolderPath);
 
             dotnetFirstTimeUseConfigurer.Configure();
 
@@ -87,7 +91,8 @@ namespace Microsoft.DotNet.Configurer.UnitTests
                 _nugetCacheSentinelMock.Object,
                 _firstTimeUseNoticeSentinelMock.Object,
                 _environmentProviderMock.Object,
-                _reporterMock.Object);
+                _reporterMock.Object,
+                CliFallbackFolderPath);
 
             dotnetFirstTimeUseConfigurer.Configure();
 
@@ -105,7 +110,8 @@ namespace Microsoft.DotNet.Configurer.UnitTests
                 _nugetCacheSentinelMock.Object,
                 _firstTimeUseNoticeSentinelMock.Object,
                 _environmentProviderMock.Object,
-                _reporterMock.Object);
+                _reporterMock.Object,
+                CliFallbackFolderPath);
 
             dotnetFirstTimeUseConfigurer.Configure();
 
@@ -123,7 +129,8 @@ namespace Microsoft.DotNet.Configurer.UnitTests
                 _nugetCacheSentinelMock.Object,
                 _firstTimeUseNoticeSentinelMock.Object,
                 _environmentProviderMock.Object,
-                _reporterMock.Object);
+                _reporterMock.Object,
+                CliFallbackFolderPath);
 
             dotnetFirstTimeUseConfigurer.Configure();
 
@@ -140,7 +147,8 @@ namespace Microsoft.DotNet.Configurer.UnitTests
                 _nugetCacheSentinelMock.Object,
                 _firstTimeUseNoticeSentinelMock.Object,
                 _environmentProviderMock.Object,
-                _reporterMock.Object);
+                _reporterMock.Object,
+                CliFallbackFolderPath);
 
             dotnetFirstTimeUseConfigurer.Configure();
 
@@ -157,7 +165,8 @@ namespace Microsoft.DotNet.Configurer.UnitTests
                 _nugetCacheSentinelMock.Object,
                 _firstTimeUseNoticeSentinelMock.Object,
                 _environmentProviderMock.Object,
-                _reporterMock.Object);
+                _reporterMock.Object,
+                CliFallbackFolderPath);
 
             dotnetFirstTimeUseConfigurer.Configure();
 
@@ -177,7 +186,8 @@ namespace Microsoft.DotNet.Configurer.UnitTests
                 _nugetCacheSentinelMock.Object,
                 _firstTimeUseNoticeSentinelMock.Object,
                 _environmentProviderMock.Object,
-                _reporterMock.Object);
+                _reporterMock.Object,
+                CliFallbackFolderPath);
 
             dotnetFirstTimeUseConfigurer.Configure();
 
@@ -194,7 +204,8 @@ namespace Microsoft.DotNet.Configurer.UnitTests
                 _nugetCacheSentinelMock.Object,
                 _firstTimeUseNoticeSentinelMock.Object,
                 _environmentProviderMock.Object,
-                _reporterMock.Object);
+                _reporterMock.Object,
+                CliFallbackFolderPath);
 
             dotnetFirstTimeUseConfigurer.Configure();
 
@@ -212,7 +223,8 @@ namespace Microsoft.DotNet.Configurer.UnitTests
                 _nugetCacheSentinelMock.Object,
                 _firstTimeUseNoticeSentinelMock.Object,
                 _environmentProviderMock.Object,
-                _reporterMock.Object);
+                _reporterMock.Object,
+                CliFallbackFolderPath);
 
             dotnetFirstTimeUseConfigurer.Configure();
 

test/Microsoft.DotNet.Configurer.UnitTests/GivenANuGetCachePrimer.cs

@@ -26,7 +26,6 @@ namespace Microsoft.DotNet.Configurer.UnitTests
 
         private Mock<INuGetPackagesArchiver> _nugetPackagesArchiverMock;
         private Mock<INuGetCacheSentinel> _nugetCacheSentinel;
-        private Mock<INuGetConfig> _nugetConfigMock;
         private CliFallbackFolderPathCalculator _cliFallbackFolderPathCalculator;
 
         public GivenANuGetCachePrimer()
@@ -41,14 +40,11 @@ namespace Microsoft.DotNet.Configurer.UnitTests
 
             _nugetCacheSentinel = new Mock<INuGetCacheSentinel>();
 
-            _nugetConfigMock = new Mock<INuGetConfig>();
-
             _cliFallbackFolderPathCalculator = new CliFallbackFolderPathCalculator();
 
             var nugetCachePrimer = new NuGetCachePrimer(
                 _nugetPackagesArchiverMock.Object,
                 _nugetCacheSentinel.Object,
-                _nugetConfigMock.Object,
                 _cliFallbackFolderPathCalculator,
                 _fileSystemMock.File);
 
@@ -67,7 +63,6 @@ namespace Microsoft.DotNet.Configurer.UnitTests
             var nugetCachePrimer = new NuGetCachePrimer(
                 nugetPackagesArchiverMock.Object,
                 _nugetCacheSentinel.Object,
-                _nugetConfigMock.Object,
                 _cliFallbackFolderPathCalculator,
                 fileSystemMock.File);
 
@@ -76,14 +71,6 @@ namespace Microsoft.DotNet.Configurer.UnitTests
             nugetPackagesArchiverMock.Verify(n => n.ExtractArchive(It.IsAny<string>()), Times.Never);
         }
 
-        [Fact]
-        public void It_adds_the_fallback_folder_to_NuGet_Config()
-        {
-            _nugetConfigMock.Verify(n =>
-                n.AddCliFallbackFolder(_cliFallbackFolderPathCalculator.CliFallbackFolderPath),
-                Times.Exactly(1));
-        }
-
         [Fact]
         public void It_extracts_the_archive_to_the_fallback_folder()
         {
@@ -108,7 +95,6 @@ namespace Microsoft.DotNet.Configurer.UnitTests
             var nugetCachePrimer = new NuGetCachePrimer(
                 nugetPackagesArchiveMock.Object,
                 nugetCacheSentinel.Object,
-                _nugetConfigMock.Object,
                 _cliFallbackFolderPathCalculator,
                 _fileSystemMock.File);
 

test/Microsoft.DotNet.Configurer.UnitTests/GivenANuGetCacheSentinel.cs

@@ -2,12 +2,14 @@
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
 using System;
+using System.Collections.Generic;
 using System.IO;
 using FluentAssertions;
 using Microsoft.DotNet.Cli.Utils;
 using Microsoft.DotNet.Configurer;
 using Microsoft.Extensions.DependencyModel.Tests;
 using Microsoft.Extensions.EnvironmentAbstractions;
+using Moq;
 using Xunit;
 
 namespace Microsoft.DotNet.Configurer.UnitTests
@@ -26,18 +28,44 @@ namespace Microsoft.DotNet.Configurer.UnitTests
         [Fact]
         public void As_soon_as_it_gets_created_it_tries_to_get_handle_of_the_InProgress_sentinel()
         {
+            var fileSystemMock = _fileSystemMockBuilder.Build();
             var fileMock = new FileMock();
-            var nugetCacheSentinel = new NuGetCacheSentinel(NUGET_CACHE_PATH, fileMock);
+            var nugetCacheSentinel =
+                new NuGetCacheSentinel(NUGET_CACHE_PATH, fileMock, fileSystemMock.Directory);
 
             fileMock.OpenFileWithRightParamsCalled.Should().BeTrue();
         }
 
         [Fact]
-        public void It_returns_true_to_the_in_progress_sentinel_already_exists_when_it_fails_to_get_a_handle_to_it()
+        public void It_sets_UnauthorizedAccess_to_false_when_no_UnauthorizedAccessException_happens()
+        {
+            var fileSystemMock = _fileSystemMockBuilder.Build();
+            var fileMock = new FileMock();
+            var nugetCacheSentinel =
+                new NuGetCacheSentinel(NUGET_CACHE_PATH, fileMock, fileSystemMock.Directory);
+
+            nugetCacheSentinel.UnauthorizedAccess.Should().BeFalse();
+        }
+
+        [Fact]
+        public void It_sets_UnauthorizedAccess_to_true_when_an_UnauthorizedAccessException_happens()
         {
+            var fileMock = new FileMock();
+            var directoryMock = new DirectoryMock();
+            var nugetCacheSentinel =
+                new NuGetCacheSentinel(NUGET_CACHE_PATH, fileMock, directoryMock);
+
+            nugetCacheSentinel.UnauthorizedAccess.Should().BeTrue();
+        }
+
+        [Fact]
+        public void It_returns_true_to_the_in_progress_sentinel_already_exists_when_it_fails_to_get_a_handle_to_it()
+        {
+            var fileSystemMock = _fileSystemMockBuilder.Build();
             var fileMock = new FileMock();
             fileMock.InProgressSentinel = null;
-            var nugetCacheSentinel = new NuGetCacheSentinel(NUGET_CACHE_PATH, fileMock);
+            var nugetCacheSentinel =
+                new NuGetCacheSentinel(NUGET_CACHE_PATH, fileMock, fileSystemMock.Directory);
 
             nugetCacheSentinel.InProgressSentinelAlreadyExists().Should().BeTrue();
         }
@@ -45,9 +73,11 @@ namespace Microsoft.DotNet.Configurer.UnitTests
         [Fact]
         public void It_returns_false_to_the_in_progress_sentinel_already_exists_when_it_succeeds_in_getting_a_handle_to_it()
         {
+            var fileSystemMock = _fileSystemMockBuilder.Build();
             var fileMock = new FileMock();
             fileMock.InProgressSentinel = new MemoryStream();
-            var nugetCacheSentinel = new NuGetCacheSentinel(NUGET_CACHE_PATH, fileMock);
+            var nugetCacheSentinel =
+                new NuGetCacheSentinel(NUGET_CACHE_PATH, fileMock, fileSystemMock.Directory);
 
             nugetCacheSentinel.InProgressSentinelAlreadyExists().Should().BeFalse();
         }
@@ -55,10 +85,12 @@ namespace Microsoft.DotNet.Configurer.UnitTests
         [Fact]
         public void It_disposes_of_the_handle_to_the_InProgressSentinel_when_NuGetCacheSentinel_is_disposed()
         {
+            var fileSystemMock = _fileSystemMockBuilder.Build();
             var mockStream = new MockStream();
             var fileMock = new FileMock();
             fileMock.InProgressSentinel = mockStream;
-            using (var nugetCacheSentinel = new NuGetCacheSentinel(NUGET_CACHE_PATH, fileMock))
+            using (var nugetCacheSentinel =
+                new NuGetCacheSentinel(NUGET_CACHE_PATH, fileMock, fileSystemMock.Directory))
             {}
 
             mockStream.IsDisposed.Should().BeTrue();
@@ -77,7 +109,8 @@ namespace Microsoft.DotNet.Configurer.UnitTests
 
             var fileSystemMock = _fileSystemMockBuilder.Build();
 
-            var nugetCacheSentinel = new NuGetCacheSentinel(NUGET_CACHE_PATH, fileSystemMock.File);
+            var nugetCacheSentinel =
+                new NuGetCacheSentinel(NUGET_CACHE_PATH, fileSystemMock.File, fileSystemMock.Directory);
 
             nugetCacheSentinel.Exists().Should().BeTrue();
         }
@@ -87,7 +120,8 @@ namespace Microsoft.DotNet.Configurer.UnitTests
         {
             var fileSystemMock = _fileSystemMockBuilder.Build();
 
-            var nugetCacheSentinel = new NuGetCacheSentinel(NUGET_CACHE_PATH, fileSystemMock.File);
+            var nugetCacheSentinel =
+                new NuGetCacheSentinel(NUGET_CACHE_PATH, fileSystemMock.File, fileSystemMock.Directory);
 
             nugetCacheSentinel.Exists().Should().BeFalse();
         }
@@ -96,7 +130,8 @@ namespace Microsoft.DotNet.Configurer.UnitTests
         public void It_creates_the_sentinel_in_the_nuget_cache_path_if_it_does_not_exist_already()
         {
             var fileSystemMock = _fileSystemMockBuilder.Build();
-            var nugetCacheSentinel = new NuGetCacheSentinel(NUGET_CACHE_PATH, fileSystemMock.File);
+            var nugetCacheSentinel =
+                new NuGetCacheSentinel(NUGET_CACHE_PATH, fileSystemMock.File, fileSystemMock.Directory);
 
             nugetCacheSentinel.Exists().Should().BeFalse();
 
@@ -114,7 +149,8 @@ namespace Microsoft.DotNet.Configurer.UnitTests
 
             var fileSystemMock = _fileSystemMockBuilder.Build();
 
-            var nugetCacheSentinel = new NuGetCacheSentinel(NUGET_CACHE_PATH, fileSystemMock.File);
+            var nugetCacheSentinel =
+                new NuGetCacheSentinel(NUGET_CACHE_PATH, fileSystemMock.File, fileSystemMock.Directory);
 
             nugetCacheSentinel.Exists().Should().BeTrue();
 
@@ -123,6 +159,34 @@ namespace Microsoft.DotNet.Configurer.UnitTests
             fileSystemMock.File.ReadAllText(sentinel).Should().Be(contentToValidateSentinalWasNotReplaced);
         }
 
+        private class DirectoryMock : IDirectory
+        {
+            public bool Exists(string path)
+            {
+                return false;
+            }
+
+            public ITemporaryDirectory CreateTemporaryDirectory()
+            {
+                throw new NotImplementedException();
+            }
+
+            public IEnumerable<string> GetFiles(string path, string searchPattern)
+            {
+                throw new NotImplementedException();
+            }
+
+            public string GetDirectoryFullName(string path)
+            {
+                throw new NotImplementedException();
+            }
+
+            public void CreateDirectory(string path)
+            {
+                throw new UnauthorizedAccessException();
+            }
+        }
+
         private class FileMock : IFile
         {
             public bool OpenFileWithRightParamsCalled { get; private set; }

test/Microsoft.DotNet.Configurer.UnitTests/GivenANuGetConfig.cs

@@ -1,53 +0,0 @@
-// Copyright (c) .NET Foundation and contributors. All rights reserved.
-// Licensed under the MIT license. See LICENSE file in the project root for full license information.
-
-using System.Collections.Generic;
-using FluentAssertions;
-using Moq;
-using NuGet.Configuration;
-using Xunit;
-
-namespace Microsoft.DotNet.Configurer.UnitTests
-{
-    public class GivenANuGetConfig
-    {
-        private const string PathToFallbackFolderAlreadySet = "some path to fallback folder";
-
-        private Mock<ISettings> _settingsMock;
-        private INuGetConfig _nugetConfig;
-
-        public GivenANuGetConfig()
-        {
-            _settingsMock = new Mock<ISettings>();
-            _settingsMock
-                .Setup(s => s.GetSettingValues(NuGetConfig.FallbackPackageFolders, false))
-                .Returns(new List<SettingValue>()
-                {
-                    new SettingValue("CliFallbackFolder", PathToFallbackFolderAlreadySet, false)
-                });
-
-            _nugetConfig = new NuGetConfig(_settingsMock.Object);
-        }
-
-        [Fact]
-        public void ItAddsACliFallbackFolderIfOneIsNotPresentAlready()
-        {
-            const string FallbackFolderNotAlreadySet = "some path not already set";
-            _nugetConfig.AddCliFallbackFolder(FallbackFolderNotAlreadySet);
-
-            _settingsMock.Verify(s =>
-                s.SetValue(NuGetConfig.FallbackPackageFolders, "CliFallbackFolder", FallbackFolderNotAlreadySet),
-                Times.Exactly(1));
-        }
-
-        [Fact]
-        public void ItDoesNotAddTheCliFallbackFolderIfItIsAlreadyPresent()
-        {
-            _nugetConfig.AddCliFallbackFolder(PathToFallbackFolderAlreadySet);
-
-            _settingsMock.Verify(s => 
-                s.SetValue(NuGetConfig.FallbackPackageFolders, "CliFallbackFolder", PathToFallbackFolderAlreadySet),
-                Times.Never);
-        }
-    }
-}

test/Microsoft.DotNet.Tools.Tests.Utilities/Mock/FileSystemMockBuilder.cs

@@ -138,6 +138,11 @@ namespace Microsoft.Extensions.DependencyModel.Tests
             {
                 return _files.Keys.Any(k => k.StartsWith(path));
             }
+
+            public void CreateDirectory(string path)
+            {
+                _files.Add(path, path);
+            }
         }
 
         private class TemporaryDirectoryMock : ITemporaryDirectoryMock

test/dotnet-msbuild.Tests/GivenDotnetMSBuildBuildsProjects.cs

@@ -109,7 +109,7 @@ namespace Microsoft.DotNet.Cli.MSBuild.Tests
 
             result.Should().Fail();
 
-            result.StdOut.Should().ContainVisuallySameFragment(@"source(s): /usr/local/bin, nuget.org");
+            result.StdOut.Should().ContainVisuallySameFragment("NU1101");
         }
 
         [Fact]
@@ -186,14 +186,17 @@ namespace Microsoft.DotNet.Cli.MSBuild.Tests
         }
     }
 
-    public sealed class MockNuGetCacheSentinel : INuGetCacheSentinel
+    public sealed class MockNuGetCacheSentinel : IFirstTimeUseNoticeSentinel
     {
         private readonly Func<bool> _exists;
 
+        public bool UnauthorizedAccess => true;
+
         public MockNuGetCacheSentinel(Func<bool> exists = null)
         {
             _exists = exists ?? (() => true);
         }
+
         public void Dispose()
         {
         }

test/dotnet.Tests/GivenThatTheUserIsRunningDotNetForTheFirstTime.cs

@@ -25,19 +25,21 @@ namespace Microsoft.DotNet.Tests
         {
             var testDirectory = TestAssets.CreateTestDirectory("Dotnet_first_time_experience_tests");
             var testNuGetHome = Path.Combine(testDirectory.FullName, "nuget_home");
+            var cliTestFallbackFolder = Path.Combine(testNuGetHome, ".dotnet", "NuGetFallbackFolder");
 
             var command = new DotnetCommand()
                 .WithWorkingDirectory(testDirectory);
             command.Environment["HOME"] = testNuGetHome;
             command.Environment["USERPROFILE"] = testNuGetHome;
             command.Environment["APPDATA"] = testNuGetHome;
+            command.Environment["DOTNET_CLI_TEST_FALLBACKFOLDER"] = cliTestFallbackFolder;
             command.Environment["DOTNET_SKIP_FIRST_TIME_EXPERIENCE"] = "";
             command.Environment["SkipInvalidConfigurations"] = "true";
 
             _firstDotnetNonVerbUseCommandResult = command.ExecuteWithCapturedOutput("--info");
             _firstDotnetVerbUseCommandResult = command.ExecuteWithCapturedOutput("new --debug:ephemeral-hive");
 
-            _nugetFallbackFolder = new DirectoryInfo(Path.Combine(testNuGetHome, ".dotnet", "NuGetFallbackFolder"));
+            _nugetFallbackFolder = new DirectoryInfo(cliTestFallbackFolder);
         }
 
         [Fact]