diff --git a/chrome/content/zotero/hardConfirmationDialog.js b/chrome/content/zotero/hardConfirmationDialog.js
index 5b03998102..44809c77b6 100644
--- a/chrome/content/zotero/hardConfirmationDialog.js
+++ b/chrome/content/zotero/hardConfirmationDialog.js
@@ -25,16 +25,24 @@
 
 Zotero.HardConfirmationDialog = {
 	init: function() {
-		var label, content;
 		this.io = window.arguments[0];
 		
+		Zotero.setFontSize(document.getElementById('zotero-hardConfirmationDialog'));
+		
 		var vbox = document.getElementById('infoContainer');
 		var sep = vbox.firstChild;
-		for (let text of this.io.text) {
-			label = document.createElement('label');
-			content = document.createTextNode(text);
-			label.appendChild(content);
-			vbox.insertBefore(label, sep);
+		
+		document.getElementById('infoBody').textContent = this.io.text;
+		
+		if (this.io.title) {
+			document.documentElement.setAttribute('title', this.io.title);
+			
+			if (Zotero.isMac) {
+				let elem = document.getElementById('infoTitle');
+				elem.textContent = this.io.title;
+				elem.style.marginBottom = '12px';
+				elem.hidden = false;
+			}
 		}
 		if (this.io.checkboxLabel) {
 			var checkbox = document.getElementById('zotero-hardConfirmationDialog-checkbox');
@@ -47,14 +55,17 @@ Zotero.HardConfirmationDialog = {
 			this.onKeyUp();
 		}
 		
+		if (this.io.acceptLabel) {
+			document.documentElement.getButton('accept').label = this.io.acceptLabel
+		}
 		if (this.io.extra1Label) {
 			document.documentElement.buttons = document.documentElement.buttons + ',extra1';
 			document.documentElement.getButton('extra1').label = this.io.extra1Label
-		} if (this.io.acceptLabel) {
-			document.documentElement.getButton('accept').label = this.io.acceptLabel
 		}
-		
-		document.documentElement.setAttribute('title', this.io.title);
+		if (this.io.extra2Label) {
+			document.documentElement.buttons = document.documentElement.buttons + ',extra2';
+			document.documentElement.getButton('extra2').label = this.io.extra2Label
+		}
 	},
 	
 	onCheckbox: function(event) {
@@ -74,5 +85,10 @@ Zotero.HardConfirmationDialog = {
 	onExtra1: function() {
 		this.io.extra1 = true;
 		document.documentElement.cancelDialog();
+	},
+	
+	onExtra2: function() {
+		this.io.extra2 = true;
+		document.documentElement.cancelDialog();
 	}
 };
diff --git a/chrome/content/zotero/hardConfirmationDialog.xul b/chrome/content/zotero/hardConfirmationDialog.xul
index c3c6d5f6a0..771f1e64a6 100644
--- a/chrome/content/zotero/hardConfirmationDialog.xul
+++ b/chrome/content/zotero/hardConfirmationDialog.xul
@@ -28,6 +28,7 @@
 <?xml-stylesheet href="chrome://global/skin/" type="text/css"?>
 <?xml-stylesheet href="chrome://global/content/commonDialog.css" type="text/css"?>
 <?xml-stylesheet href="chrome://global/skin/commonDialog.css" type="text/css"?>
+<?xml-stylesheet href="chrome://zotero/skin/hardConfirmationDialog.css" type="text/css"?>
 
 <!DOCTYPE overlay [ <!ENTITY % zoteroDTD SYSTEM "chrome://zotero/locale/zotero.dtd"> %zoteroDTD; ]>
 
@@ -36,7 +37,8 @@
 	id="zotero-hardConfirmationDialog"
 	onload="Zotero.HardConfirmationDialog.init(); sizeToContent();"
 	ondialogaccept="Zotero.HardConfirmationDialog.onAccept();"
-	ondialogextra1="Zotero.HardConfirmationDialog.onExtra1();">
+	ondialogextra1="Zotero.HardConfirmationDialog.onExtra1();"
+	ondialogextra2="Zotero.HardConfirmationDialog.onExtra2();">
 	
 	<script src="chrome://zotero/content/include.js"/>
 	<script src="hardConfirmationDialog.js"/>
@@ -50,6 +52,9 @@
 			<row>
 				<hbox id="iconContainer" align="start"><image id="info.icon" class="spaced alert-icon"/></hbox>
 				<vbox id="infoContainer">
+					<description id="infoTitle" hidden="true"/>
+					<description id="infoBody"/>
+					
 					<separator class="thin"/>
 
 					<checkbox id="zotero-hardConfirmationDialog-checkbox" hidden="true" oncommand="Zotero.HardConfirmationDialog.onCheckbox(event)"/>
diff --git a/chrome/content/zotero/xpcom/sync/syncLocal.js b/chrome/content/zotero/xpcom/sync/syncLocal.js
index fc47832ba4..adea783bff 100644
--- a/chrome/content/zotero/xpcom/sync/syncLocal.js
+++ b/chrome/content/zotero/xpcom/sync/syncLocal.js
@@ -126,13 +126,21 @@ Zotero.Sync.Data.Local = {
 				+ `last username '${lastUsername}', current username '${username}'`, 2);
 			var io = {
 				title: Zotero.getString('general.warning'),
-				text: [Zotero.getString('account.lastSyncWithDifferentAccount', [ZOTERO_CONFIG.CLIENT_NAME, lastUsername, username])],
-				checkboxLabel: Zotero.getString('account.confirmDelete'),
-				acceptLabel: Zotero.getString('account.confirmDelete.button')
+				text: Zotero.getString(
+						'account.lastSyncWithDifferentAccount',
+						[Zotero.appName, lastUsername, username]
+					) + '\n\n'
+					+ Zotero.getString(
+						'account.lastSyncWithDifferentAccount.beforeContinuing',
+						[lastUsername, Zotero.appName]
+					),
+				checkboxLabel: Zotero.getString('account.confirmDelete', lastUsername),
+				acceptLabel: Zotero.getString('account.confirmDelete.button'),
+				extra2Label: Zotero.getString('general.moreInformation')
 			};
 			win.openDialog("chrome://zotero/content/hardConfirmationDialog.xul", "",
-				"chrome, dialog, modal, centerscreen", io);
-					
+				"chrome,dialog,modal,centerscreen", io);
+			
 			if (io.accept) {
 				var resetDataDirFile = OS.Path.join(Zotero.DataDirectory.dir, 'reset-data-directory');
 				yield Zotero.File.putContentsAsync(resetDataDirFile, '');
@@ -150,6 +158,9 @@ Zotero.Sync.Data.Local = {
 				
 				return true;
 			}
+			else if (io.extra2) {
+				Zotero.launchURL("https://www.zotero.org/support/kb/switching_accounts");
+			}
 			
 			return false;
 		}
diff --git a/chrome/locale/en-US/zotero/zotero.properties b/chrome/locale/en-US/zotero/zotero.properties
index 46438b5b41..a4682cd31f 100644
--- a/chrome/locale/en-US/zotero/zotero.properties
+++ b/chrome/locale/en-US/zotero/zotero.properties
@@ -984,8 +984,9 @@ account.unlinkWarning.removeData		= Remove my %S data from this computer
 account.unlinkWarning.button			= Unlink Account
 account.warning.emptyLibrary			= You are about to sync the ‘%1$S’ account to an empty %2$S database. This could happen if you removed your previous database or if the location of your %2$S data directory changed.
 account.warning.existingDataElsewhere	= If your %S data exists elsewhere on this computer, you should move it to the current data directory or change the data directory location to point to your existing data.
-account.lastSyncWithDifferentAccount	= This %1$S database was last synced with a different account (‘%2$S’) from the current one (‘%3$S’). If you continue, data associated with the ‘%2$S’ account will be removed from this computer.
-account.confirmDelete					= Remove existing data
+account.lastSyncWithDifferentAccount	= This %1$S database was last synced with a different account (“%2$S”) from the one you are attempting to sync with (“%3$S”). If you continue, all %1$S libraries associated with the “%2$S” account will be removed from this computer.
+account.lastSyncWithDifferentAccount.beforeContinuing = Before continuing, make sure all data and files you wish to keep have been synced with the “%S” account or you have a backup of your %S data directory.
+account.confirmDelete					= Remove all data for “%S” from this computer
 account.confirmDelete.button			= Switch Accounts
 
 sync.conflict.autoChange.alert			= One or more locally deleted Zotero %S have been modified remotely since the last sync.
diff --git a/chrome/skin/default/zotero/hardConfirmationDialog.css b/chrome/skin/default/zotero/hardConfirmationDialog.css
new file mode 100644
index 0000000000..b47a1b2858
--- /dev/null
+++ b/chrome/skin/default/zotero/hardConfirmationDialog.css
@@ -0,0 +1,11 @@
+#zotero-hardConfirmationDialog {
+	max-width: 500px;
+}
+
+#zotero-hardConfirmationDialog-checkbox {
+	font: menu;
+}
+
+#infoContainer {
+	margin-bottom: 6px;
+}
\ No newline at end of file
diff --git a/test/tests/syncLocalTest.js b/test/tests/syncLocalTest.js
index f8d2bc0670..0c8a84d4e4 100644
--- a/test/tests/syncLocalTest.js
+++ b/test/tests/syncLocalTest.js
@@ -45,11 +45,12 @@ describe("Zotero.Sync.Data.Local", function() {
 			var handled = false;
 			waitForDialog(function (dialog) {
 				var text = dialog.document.documentElement.textContent;
-				var matches = text.match(/‘[^’]*’/g);
-				assert.equal(matches.length, 3);
-				assert.equal(matches[0], "‘A’");
-				assert.equal(matches[1], "‘B’");
-				assert.equal(matches[2], "‘A’");
+				var matches = text.match(/“[^”]*”/g);
+				assert.equal(matches.length, 4);
+				assert.equal(matches[0], "“A”");
+				assert.equal(matches[1], "“B”");
+				assert.equal(matches[2], "“A”");
+				assert.equal(matches[3], "“A”");
 				
 				dialog.document.getElementById('zotero-hardConfirmationDialog-checkbox').checked = true;
 				dialog.document.getElementById('zotero-hardConfirmationDialog-checkbox')