Store settings in %AppData%\ICSharpCode\SharpDevelop${major} instead of major.minor so that SD 4.1 and 4.2 will share settings.

src/Main/StartUp/Project/SharpDevelopMain.cs

@@ -159,7 +159,7 @@ namespace ICSharpCode.SharpDevelop
 				string configDirectory = ConfigurationManager.AppSettings["settingsPath"];
 				if (String.IsNullOrEmpty(configDirectory)) {
 					startup.ConfigDirectory = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
-					                                       "ICSharpCode/SharpDevelop" + RevisionClass.Major + "." + RevisionClass.Minor);
+					                                       "ICSharpCode/SharpDevelop" + RevisionClass.Major);
 				} else {
 					startup.ConfigDirectory = Path.Combine(Path.GetDirectoryName(exe.Location), configDirectory);
 				}