diff --git a/QuickLook.Common b/QuickLook.Common
index 5c035ca..4ea4cfc 160000
--- a/QuickLook.Common
+++ b/QuickLook.Common
@@ -1 +1 @@
-Subproject commit 5c035caf526ea90f9b2b6d15a9d7bbb5a9cd0b68
+Subproject commit 4ea4cfc971e8d218fbcc2a4ea662dcada8145117
diff --git a/QuickLook/App.xaml.cs b/QuickLook/App.xaml.cs
index ea739b9..cd70907 100644
--- a/QuickLook/App.xaml.cs
+++ b/QuickLook/App.xaml.cs
@@ -39,8 +39,9 @@ namespace QuickLook
         public static readonly bool IsUWP = ProcessHelper.IsRunningAsUWP();
         public static readonly bool IsWin10 = Environment.OSVersion.Version >= new Version(10, 0);
         public static readonly bool IsGPUInBlacklist = SystemHelper.IsGPUInBlacklist();
+        public static readonly bool IsPortable = SettingHelper.IsPortableVersion();
 
-        private bool _isFirstInstance;
+        private bool _cleanExit;
         private Mutex _isRunning;
 
         protected override void OnStartup(StartupEventArgs e)
@@ -55,26 +56,11 @@ namespace QuickLook
 
         private void Application_Startup(object sender, StartupEventArgs e)
         {
-            if (ProcessHelper.IsOnWindows10S())
+            if (!EnsureOSVersion()
+                || !EnsureFirstInstance(e.Args)
+                || !EnsureFolderWritable(SettingHelper.LocalDataPath))
             {
-                MessageBox.Show("This application does not run on Windows 10 S.");
-
-                Shutdown();
-                return;
-            }
-
-            EnsureFirstInstance();
-
-            if (!_isFirstInstance)
-            {
-                // second instance: preview this file
-                if (e.Args.Any() && (Directory.Exists(e.Args.First()) || File.Exists(e.Args.First())))
-                    RemoteCallShowPreview(e);
-                // second instance: duplicate
-                else
-                    MessageBox.Show(TranslationHelper.Get("APP_SECOND_TEXT"), TranslationHelper.Get("APP_SECOND"),
-                        MessageBoxButton.OK, MessageBoxImage.Information);
-
+                _cleanExit = false;
                 Shutdown();
                 return;
             }
@@ -84,7 +70,35 @@ namespace QuickLook
 
             // first instance: run and preview this file
             if (e.Args.Any() && (Directory.Exists(e.Args.First()) || File.Exists(e.Args.First())))
-                RemoteCallShowPreview(e);
+                PipeServerManager.SendMessage(PipeMessages.Toggle, e.Args.First());
+        }
+
+        private bool EnsureOSVersion()
+        {
+            if (!ProcessHelper.IsOnWindows10S())
+                return true;
+
+            MessageBox.Show("This application does not run on Windows 10 S.");
+
+            return false;
+        }
+
+        private bool EnsureFolderWritable(string folder)
+        {
+            try
+            {
+                var path = FileHelper.CreateTempFile(folder);
+                File.Delete(path);
+            }
+            catch
+            {
+                MessageBox.Show(string.Format(TranslationHelper.Get("APP_PATH_NOT_WRITABLE"), folder), "QuickLook",
+                    MessageBoxButton.OK, MessageBoxImage.Error);
+
+                return false;
+            }
+
+            return true;
         }
 
         private void CheckUpdate()
@@ -96,11 +110,6 @@ namespace QuickLook
             SettingHelper.Set("LastUpdateTicks", DateTime.Now.Ticks);
         }
 
-        private void RemoteCallShowPreview(StartupEventArgs e)
-        {
-            PipeServerManager.SendMessage(PipeMessages.Toggle, e.Args.First());
-        }
-
         private void RunListener(StartupEventArgs e)
         {
             TrayIconManager.GetInstance();
@@ -119,7 +128,7 @@ namespace QuickLook
 
         private void App_OnExit(object sender, ExitEventArgs e)
         {
-            if (!_isFirstInstance)
+            if (!_cleanExit)
                 return;
 
             _isRunning.ReleaseMutex();
@@ -130,9 +139,24 @@ namespace QuickLook
             ViewWindowManager.GetInstance().Dispose();
         }
 
-        private void EnsureFirstInstance()
+        private bool EnsureFirstInstance(string[] args)
         {
-            _isRunning = new Mutex(true, "QuickLook.App.Mutex", out _isFirstInstance);
+            _isRunning = new Mutex(true, "QuickLook.App.Mutex", out bool isFirst);
+
+            if (isFirst)
+                return true;
+
+            // second instance: preview this file
+            if (args.Any() && (Directory.Exists(args.First()) || File.Exists(args.First())))
+            {
+                PipeServerManager.SendMessage(PipeMessages.Toggle, args.First());
+            }
+            // second instance: duplicate
+            else
+                MessageBox.Show(TranslationHelper.Get("APP_SECOND_TEXT"), TranslationHelper.Get("APP_SECOND"),
+                    MessageBoxButton.OK, MessageBoxImage.Information);
+
+            return false;
         }
     }
 }
\ No newline at end of file
diff --git a/QuickLook/Translations.config b/QuickLook/Translations.config
index ad8ead5..77573e2 100644
--- a/QuickLook/Translations.config
+++ b/QuickLook/Translations.config
@@ -153,6 +153,7 @@
     <APP_START>QuickLook is running in the background.</APP_START>
     <APP_SECOND>QuickLook is already running</APP_SECOND>
     <APP_SECOND_TEXT>QuickLook enables quick previewing of certain type of files by pressing the spacebar while it is highlighted.</APP_SECOND_TEXT>
+    <APP_PATH_NOT_WRITABLE>Data path "{0}" is not writable. Please check if you have sufficient premission.</APP_PATH_NOT_WRITABLE>
     <MW_BrowseFolder>Browse {0}</MW_BrowseFolder>
     <MW_Open>Open {0}</MW_Open>
     <MW_OpenWith>Open with {0}</MW_OpenWith>
@@ -489,6 +490,7 @@
     <APP_START>QuickLook 正在后台运行。</APP_START>
     <APP_SECOND>另一个 QuickLook 进程正在运行</APP_SECOND>
     <APP_SECOND_TEXT>在您选中文件并按下空格键时，QuickLook 将提供多种格式的快速预览。</APP_SECOND_TEXT>
+    <APP_PATH_NOT_WRITABLE>数据目录 "{0}" 不可写。请检查您是否有足够的权限。</APP_PATH_NOT_WRITABLE>
     <MW_BrowseFolder>浏览 {0}</MW_BrowseFolder>
     <MW_Open>打开 {0}</MW_Open>
     <MW_OpenWith>用 {0} 打开</MW_OpenWith>
@@ -514,6 +516,7 @@
     <APP_START>QuickLook 正在背景執行</APP_START>
     <APP_SECOND>另一個 QuickLook 處理程序正在執行。</APP_SECOND>
     <APP_SECOND_TEXT>在資料夾中選取任意檔案並按下空白鍵，QuickLook 即可提供多種檔案格式的快速預覽。</APP_SECOND_TEXT>
+    <APP_PATH_NOT_WRITABLE>數據目錄 "{0}" 不可寫。請檢查您是否有足夠的權限。</APP_PATH_NOT_WRITABLE>
     <MW_BrowseFolder>瀏覽 {0}</MW_BrowseFolder>
     <MW_Open>開啟 {0}</MW_Open>
     <MW_OpenWith>使用 {0} 開啟</MW_OpenWith>
diff --git a/Scripts/pack-zip.ps1 b/Scripts/pack-zip.ps1
index c0869c7..b0b7bdc 100644
--- a/Scripts/pack-zip.ps1
+++ b/Scripts/pack-zip.ps1
@@ -2,5 +2,9 @@ $version = git describe --always --tags
 
 Start-Sleep -s 1
 
+Write-Output "This file makes QuickLook portable." >> ..\Build\Package\portable.lock
+
 Remove-Item ..\Build\QuickLook-$version.zip -ErrorAction SilentlyContinue
-Compress-Archive ..\Build\Package\* ..\Build\QuickLook-$version.zip
\ No newline at end of file
+Compress-Archive ..\Build\Package\* ..\Build\QuickLook-$version.zip
+
+Remove-Item ..\Build\Package\portable.lock
\ No newline at end of file