diff --git a/src/Microsoft.DotNet.ProjectModel/Resolution/FrameworkReferenceResolver.cs b/src/Microsoft.DotNet.ProjectModel/Resolution/FrameworkReferenceResolver.cs
index e279a695e..e75860ed1 100644
--- a/src/Microsoft.DotNet.ProjectModel/Resolution/FrameworkReferenceResolver.cs
+++ b/src/Microsoft.DotNet.ProjectModel/Resolution/FrameworkReferenceResolver.cs
@@ -208,7 +208,9 @@ namespace Microsoft.DotNet.ProjectModel.Resolution
         private static FrameworkInformation GetFrameworkInformation(NuGetFramework targetFramework, string referenceAssembliesPath)
         {
             // Check for legacy frameworks
-            if (targetFramework.IsDesktop() && targetFramework.Version <= new Version(3, 5))
+            if (PlatformServices.Default.Runtime.OperatingSystemPlatform == Platform.Windows &&
+                targetFramework.IsDesktop() &&
+                targetFramework.Version <= new Version(3, 5))
             {
                 return GetLegacyFrameworkInformation(targetFramework, referenceAssembliesPath);
             }
diff --git a/src/Microsoft.Extensions.DependencyModel/Resolution/DotNetReferenceAssembliesPathResolver.cs b/src/Microsoft.Extensions.DependencyModel/Resolution/DotNetReferenceAssembliesPathResolver.cs
index 5703b8d27..eee647c6a 100644
--- a/src/Microsoft.Extensions.DependencyModel/Resolution/DotNetReferenceAssembliesPathResolver.cs
+++ b/src/Microsoft.Extensions.DependencyModel/Resolution/DotNetReferenceAssembliesPathResolver.cs
@@ -12,7 +12,7 @@ namespace Microsoft.Extensions.DependencyModel.Resolution
     {
         public static readonly string DotNetReferenceAssembliesPathEnv = "DOTNET_REFERENCE_ASSEMBLIES_PATH";
         
-        internal static string Resolve(IEnvironment envirnment)
+        internal static string Resolve(IEnvironment envirnment, IFileSystem fileSystem, IRuntimeEnvironment runtimeEnvironment)
         {
             var path = envirnment.GetEnvironmentVariable(DotNetReferenceAssembliesPathEnv);
             if (!string.IsNullOrEmpty(path))
@@ -20,17 +20,17 @@ namespace Microsoft.Extensions.DependencyModel.Resolution
                 return path;
             }
             
-            return GetDefaultDotNetReferenceAssembliesPath();
+            return GetDefaultDotNetReferenceAssembliesPath(fileSystem, runtimeEnvironment);
         }
         
         public static string Resolve()
         {
-            return Resolve(EnvironmentWrapper.Default);
+            return Resolve(EnvironmentWrapper.Default, FileSystemWrapper.Default, PlatformServices.Default.Runtime);
         }
                 
-        private static string GetDefaultDotNetReferenceAssembliesPath()
+        private static string GetDefaultDotNetReferenceAssembliesPath(IFileSystem fileSystem, IRuntimeEnvironment runtimeEnvironment)
         {            
-            var os = PlatformServices.Default.Runtime.OperatingSystemPlatform;
+            var os = runtimeEnvironment.OperatingSystemPlatform;
             
             if (os == Platform.Windows)
             {
@@ -38,17 +38,17 @@ namespace Microsoft.Extensions.DependencyModel.Resolution
             }
             
             if (os == Platform.Darwin && 
-                Directory.Exists("/Library/Framework/Mono.Framework/Versions/Current/lib/mono/xbuild-frameworks"))
+                fileSystem.Directory.Exists("/Library/Framework/Mono.Framework/Versions/Current/lib/mono/xbuild-frameworks"))
             {
                 return "/Library/Framework/Mono.Framework/Versions/Current/lib/mono/xbuild-frameworks";
             }
             
-            if (Directory.Exists("/usr/local/lib/mono/xbuild-frameworks"))
+            if (fileSystem.Directory.Exists("/usr/local/lib/mono/xbuild-frameworks"))
             {
                 return "/usr/local/lib/mono/xbuild-frameworks";
             }
             
-            if (Directory.Exists("/usr/lib/mono/xbuild-frameworks"))
+            if (fileSystem.Directory.Exists("/usr/lib/mono/xbuild-frameworks"))
             {
                 return "/usr/lib/mono/xbuild-frameworks";
             }
diff --git a/src/Microsoft.Extensions.DependencyModel/Resolution/ReferenceAssemblyPathResolver.cs b/src/Microsoft.Extensions.DependencyModel/Resolution/ReferenceAssemblyPathResolver.cs
index ffc95ca0c..55f212660 100644
--- a/src/Microsoft.Extensions.DependencyModel/Resolution/ReferenceAssemblyPathResolver.cs
+++ b/src/Microsoft.Extensions.DependencyModel/Resolution/ReferenceAssemblyPathResolver.cs
@@ -27,7 +27,7 @@ namespace Microsoft.Extensions.DependencyModel.Resolution
 
         internal ReferenceAssemblyPathResolver(IFileSystem fileSystem, IRuntimeEnvironment runtimeEnvironment, IEnvironment environment)
             : this(fileSystem,
-                GetDefaultReferenceAssembliesPath(runtimeEnvironment, environment),
+                GetDefaultReferenceAssembliesPath(runtimeEnvironment, fileSystem, environment),
                 GetFallbackSearchPaths(fileSystem, runtimeEnvironment, environment))
         {
         }
@@ -101,10 +101,10 @@ namespace Microsoft.Extensions.DependencyModel.Resolution
             return new[] { net20Dir };
         }
 
-        internal static string GetDefaultReferenceAssembliesPath(IRuntimeEnvironment runtimeEnvironment, IEnvironment environment)
+        internal static string GetDefaultReferenceAssembliesPath(IRuntimeEnvironment runtimeEnvironment, IFileSystem fileSystem, IEnvironment environment)
         {
             // Allow setting the reference assemblies path via an environment variable
-            var referenceAssembliesPath = DotNetReferenceAssembliesPathResolver.Resolve(environment); 
+            var referenceAssembliesPath = DotNetReferenceAssembliesPathResolver.Resolve(environment, fileSystem, runtimeEnvironment); 
             if (!string.IsNullOrEmpty(referenceAssembliesPath))
             {
                 return referenceAssembliesPath;
diff --git a/test/Microsoft.Extensions.DependencyModel.Tests/ReferenceAssemblyResolverTests.cs b/test/Microsoft.Extensions.DependencyModel.Tests/ReferenceAssemblyResolverTests.cs
index 7561c77dc..dbaf6589d 100644
--- a/test/Microsoft.Extensions.DependencyModel.Tests/ReferenceAssemblyResolverTests.cs
+++ b/test/Microsoft.Extensions.DependencyModel.Tests/ReferenceAssemblyResolverTests.cs
@@ -36,12 +36,12 @@ namespace Microsoft.Extensions.DependencyModel.Tests
         {
             var runtime = new Mock<IRuntimeEnvironment>();
             runtime.SetupGet(r => r.OperatingSystemPlatform).Returns(Platform.Windows);
-
+            
             var environment = EnvironmentMockBuilder.Create()
                 .AddVariable("DOTNET_REFERENCE_ASSEMBLIES_PATH", ReferencePath)
                 .Build();
 
-            var result = ReferenceAssemblyPathResolver.GetDefaultReferenceAssembliesPath(runtime.Object, environment);
+            var result = ReferenceAssemblyPathResolver.GetDefaultReferenceAssembliesPath(runtime.Object, FileSystemMockBuilder.Empty, environment);
             result.Should().Be(ReferencePath);
         }
 
@@ -51,7 +51,7 @@ namespace Microsoft.Extensions.DependencyModel.Tests
             var runtime = new Mock<IRuntimeEnvironment>();
             runtime.SetupGet(r => r.OperatingSystemPlatform).Returns(Platform.Linux);
 
-            var result = ReferenceAssemblyPathResolver.GetDefaultReferenceAssembliesPath(runtime.Object, EnvironmentMockBuilder.Empty);
+            var result = ReferenceAssemblyPathResolver.GetDefaultReferenceAssembliesPath(runtime.Object, FileSystemMockBuilder.Empty, EnvironmentMockBuilder.Empty);
             result.Should().BeNull();
         }
 
@@ -66,7 +66,7 @@ namespace Microsoft.Extensions.DependencyModel.Tests
                 .AddVariable("ProgramFiles", "Program Files")
                 .Build();
 
-            var result = ReferenceAssemblyPathResolver.GetDefaultReferenceAssembliesPath(runtime.Object, environment);
+            var result = ReferenceAssemblyPathResolver.GetDefaultReferenceAssembliesPath(runtime.Object, FileSystemMockBuilder.Empty, environment);
             result.Should().Be(Path.Combine("Program Files (x86)", "Reference Assemblies", "Microsoft", "Framework"));
         }
 
@@ -80,7 +80,7 @@ namespace Microsoft.Extensions.DependencyModel.Tests
                 .AddVariable("ProgramFiles", "Program Files")
                 .Build();
 
-            var result = ReferenceAssemblyPathResolver.GetDefaultReferenceAssembliesPath(runtime.Object, environment);
+            var result = ReferenceAssemblyPathResolver.GetDefaultReferenceAssembliesPath(runtime.Object, FileSystemMockBuilder.Empty, environment);
             result.Should().Be(Path.Combine("Program Files", "Reference Assemblies", "Microsoft", "Framework"));
         }