diff --git a/chrome/content/zotero/xpcom/sync.js b/chrome/content/zotero/xpcom/sync.js
index 12e4e5b10..fd3565ead 100644
--- a/chrome/content/zotero/xpcom/sync.js
+++ b/chrome/content/zotero/xpcom/sync.js
@@ -1228,9 +1228,18 @@ Zotero.Sync.Server = new function () {
 		}
 		catch (e) {
 			Zotero.debug(e);
-			var msg = Zotero.getString('sync.error.loginManagerCorrupted1', Zotero.appName) + "\n\n"
-						+ Zotero.getString('sync.error.loginManagerCorrupted2', [Zotero.appName, Zotero.appName]);
-			alert(msg);
+			if (Zotero.isStandalone) {
+				var msg = Zotero.getString('sync.error.loginManagerCorrupted1', Zotero.appName) + "\n\n"
+					+ Zotero.getString('sync.error.loginManagerCorrupted2', [Zotero.appName, Zotero.appName]);
+			}
+			else {
+				var msg = Zotero.getString('sync.error.loginManagerInaccessible') + "\n\n"
+					+ Zotero.getString('sync.error.checkMasterPassword', Zotero.appName) + "\n\n"
+					+ Zotero.getString('sync.error.corruptedLoginManager', Zotero.appName);
+			}
+			var ps = Components.classes["@mozilla.org/embedcomp/prompt-service;1"]
+				.getService(Components.interfaces.nsIPromptService);
+			ps.alert(null, Zotero.getString('general.error'), msg);
 			return '';
 		}
 		
diff --git a/chrome/locale/en-US/zotero/zotero.properties b/chrome/locale/en-US/zotero/zotero.properties
index ee310bf91..71ca50c46 100644
--- a/chrome/locale/en-US/zotero/zotero.properties
+++ b/chrome/locale/en-US/zotero/zotero.properties
@@ -751,7 +751,10 @@ sync.error.passwordNotSet			= Password not set
 sync.error.invalidLogin				= Invalid username or password
 sync.error.invalidLogin.text		= The Zotero sync server did not accept your username and password.\n\nPlease check that you have entered your zotero.org login information correctly in the Zotero sync preferences.
 sync.error.enterPassword			= Please enter a password.
-sync.error.loginManagerCorrupted1	= Zotero cannot access your login information, likely due to a corrupted %S login manager database.
+sync.error.loginManagerInaccessible = Zotero cannot access your login information.
+sync.error.checkMasterPassword         = If you are using a master password in %S, make sure you have entered it successfully.
+sync.error.corruptedLoginManager       = This could also be due to a corrupted %1$S login manager database. To check, close %1$S, back up and delete signons.* from your %1$S profile, and re-enter your Zotero login information in the Sync pane of the Zotero preferences.
+sync.error.loginManagerCorrupted1	= Zotero cannot access your login information, possibly due to a corrupted %S login manager database.
 sync.error.loginManagerCorrupted2	= Close %1$S, back up and delete signons.* from your %2$S profile, and re-enter your Zotero login information in the Sync pane of the Zotero preferences.
 sync.error.syncInProgress			= A sync operation is already in progress.
 sync.error.syncInProgress.wait		= Wait for the previous sync to complete or restart %S.