diff --git a/QuickLook.Plugin/QuickLook.Plugin.PluginInstaller/Plugin.cs b/QuickLook.Plugin/QuickLook.Plugin.PluginInstaller/Plugin.cs
index 5bb906a..20b3c37 100644
--- a/QuickLook.Plugin/QuickLook.Plugin.PluginInstaller/Plugin.cs
+++ b/QuickLook.Plugin/QuickLook.Plugin.PluginInstaller/Plugin.cs
@@ -19,6 +19,7 @@ using System;
 using System.IO;
 using System.Linq;
 using System.Windows;
+using QuickLook.Common.ExtensionMethods;
 using QuickLook.Common.Plugin;
 
 namespace QuickLook.Plugin.PluginInstaller
@@ -29,6 +30,7 @@ namespace QuickLook.Plugin.PluginInstaller
 
         public void Init()
         {
+            CleanupOldPlugins(App.UserPluginPath);
         }
 
         public bool CanHandle(string path)
@@ -58,5 +60,23 @@ namespace QuickLook.Plugin.PluginInstaller
         public void Cleanup()
         {
         }
+
+        private static void CleanupOldPlugins(string folder)
+        {
+            if (!Directory.Exists(folder))
+                return;
+
+            Directory.GetFiles(folder, "*.to_be_deleted", SearchOption.AllDirectories).ForEach(file =>
+            {
+                try
+                {
+                    File.Delete(file);
+                }
+                catch (Exception)
+                {
+                    // ignored
+                }
+            });
+        }
     }
 }
\ No newline at end of file
diff --git a/QuickLook.Plugin/QuickLook.Plugin.PluginInstaller/PluginInfoPanel.xaml.cs b/QuickLook.Plugin/QuickLook.Plugin.PluginInstaller/PluginInfoPanel.xaml.cs
index fe73360..db9e458 100644
--- a/QuickLook.Plugin/QuickLook.Plugin.PluginInstaller/PluginInfoPanel.xaml.cs
+++ b/QuickLook.Plugin/QuickLook.Plugin.PluginInstaller/PluginInfoPanel.xaml.cs
@@ -52,7 +52,7 @@ namespace QuickLook.Plugin.PluginInstaller
             btnInstall.Content = "Installing ...";
             btnInstall.IsEnabled = false;
 
-            var t=DoInstall();
+            var t = DoInstall();
             t.ContinueWith(_ =>
                 Dispatcher.BeginInvoke(new Action(() => btnInstall.Content = "Done! Please restart QuickLook.")));
             t.Start();
@@ -72,6 +72,7 @@ namespace QuickLook.Plugin.PluginInstaller
                 catch (Exception ex)
                 {
                     Dispatcher.BeginInvoke(new Action(() => description.Text = ex.Message));
+                    Dispatcher.BeginInvoke(new Action(() => btnInstall.Content = "Installation failed."));
                     CleanUp();
                 }
             });
@@ -87,11 +88,13 @@ namespace QuickLook.Plugin.PluginInstaller
                 try
                 {
                     Directory.GetFiles(targetFolder, "*", SearchOption.AllDirectories)
-                        .ForEach(file => File.Move(file, new Guid() + ".to_be_deleted"));
+                        .ForEach(file => File.Move(file,
+                            Path.Combine(Path.GetDirectoryName(file), Guid.NewGuid() + ".to_be_deleted")));
                 }
                 catch (Exception ex)
                 {
                     Dispatcher.BeginInvoke(new Action(() => description.Text = ex.Message));
+                    Dispatcher.BeginInvoke(new Action(() => btnInstall.Content = "Installation failed."));
                 }
             }
         }
diff --git a/QuickLook.Plugin/QuickLook.Plugin.PluginInstaller/QuickLook.Plugin.PluginInstaller.csproj b/QuickLook.Plugin/QuickLook.Plugin.PluginInstaller/QuickLook.Plugin.PluginInstaller.csproj
index 25dca7d..990d1e8 100644
--- a/QuickLook.Plugin/QuickLook.Plugin.PluginInstaller/QuickLook.Plugin.PluginInstaller.csproj
+++ b/QuickLook.Plugin/QuickLook.Plugin.PluginInstaller/QuickLook.Plugin.PluginInstaller.csproj
@@ -81,7 +81,7 @@
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\QuickLook.Common\QuickLook.Common.csproj">
-      <Project>{85FDD6BA-871D-46C8-BD64-F6BB0CB5EA95}</Project>
+      <Project>{85fdd6ba-871d-46c8-bd64-f6bb0cb5ea95}</Project>
       <Name>QuickLook.Common</Name>
       <Private>False</Private>
     </ProjectReference>
diff --git a/QuickLook/PluginManager.cs b/QuickLook/PluginManager.cs
index d465dc8..26c3c4e 100644
--- a/QuickLook/PluginManager.cs
+++ b/QuickLook/PluginManager.cs
@@ -33,7 +33,6 @@ namespace QuickLook
 
         private PluginManager()
         {
-            CleanupOldPlugins(App.UserPluginPath);
             LoadPlugins(App.UserPluginPath);
             LoadPlugins(Path.Combine(App.AppPath, "QuickLook.Plugin\\"));
             InitLoadedPlugins();
@@ -113,23 +112,5 @@ namespace QuickLook
                 }
             });
         }
-
-        private static void CleanupOldPlugins(string folder)
-        {
-            if (!Directory.Exists(folder))
-                return;
-
-            Directory.GetFiles(folder, "*.to_be_deleted", SearchOption.AllDirectories).ForEach(file =>
-            {
-                try
-                {
-                    File.Delete(file);
-                }
-                catch (Exception)
-                {
-                    // ignored
-                }
-            });
-        }
     }
 }
\ No newline at end of file