diff --git a/src/Umbraco.Web.UI/install/InstallerRestService.aspx.cs b/src/Umbraco.Web.UI/install/InstallerRestService.aspx.cs
index 248e6c17d2..8b197d75f0 100644
--- a/src/Umbraco.Web.UI/install/InstallerRestService.aspx.cs
+++ b/src/Umbraco.Web.UI/install/InstallerRestService.aspx.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Configuration;
 using System.Security.Authentication;
+using System.Web;
 using System.Web.Script.Serialization;
 using System.Web.Script.Services;
 using System.Web.Services;
@@ -97,6 +98,11 @@ namespace Umbraco.Web.UI.Install
 
             HandleConnectionStrings();
 
+            //After upgrading we must restart the app pool - the reason is because PetaPoco caches a lot of the mapping logic
+            // and after we upgrade a db, some of the mapping needs to be updated so we restart the app pool to clear it's cache or
+            // else we can end up with YSODs
+            ApplicationContext.Current.RestartApplicationPool(new HttpContextWrapper(HttpContext.Current));
+            
             var js = new JavaScriptSerializer();
             var jsonResult = js.Serialize(result);
             return jsonResult;
diff --git a/src/Umbraco.Web.UI/install/steps/Database.ascx.cs b/src/Umbraco.Web.UI/install/steps/Database.ascx.cs
index ede7132da0..45eab19d45 100644
--- a/src/Umbraco.Web.UI/install/steps/Database.ascx.cs
+++ b/src/Umbraco.Web.UI/install/steps/Database.ascx.cs
@@ -161,10 +161,10 @@ namespace Umbraco.Web.UI.Install.Steps
             DatabasePassword.Text = GetConnectionStringValue(connectionStringBuilder, "password");
             if (string.IsNullOrEmpty(DatabasePassword.Text)) DatabasePassword.Text = GetConnectionStringValue(connectionStringBuilder, "pwd");
 
-            toggleVisible(DatabaseServerItem, !ManualConnectionString && !IsEmbeddedDatabase);
-            toggleVisible(DatabaseUsernameItem, !ManualConnectionString && !IsEmbeddedDatabase);
-            toggleVisible(DatabasePasswordItem, !ManualConnectionString && !IsEmbeddedDatabase);
-            toggleVisible(DatabaseNameItem, !ManualConnectionString && !IsEmbeddedDatabase);
+            ToggleVisible(DatabaseServerItem, !ManualConnectionString && !IsEmbeddedDatabase);
+            ToggleVisible(DatabaseUsernameItem, !ManualConnectionString && !IsEmbeddedDatabase);
+            ToggleVisible(DatabasePasswordItem, !ManualConnectionString && !IsEmbeddedDatabase);
+            ToggleVisible(DatabaseNameItem, !ManualConnectionString && !IsEmbeddedDatabase);
 
             if (IsNewInstall || IsEmbeddedDatabase)
                 dbinit.Text = "$('#databaseOptionEmbedded').click();$('#databaseOptionEmbedded').change();";
@@ -243,15 +243,15 @@ namespace Umbraco.Web.UI.Install.Steps
         /// <param name="e">The event arguments.</param>
         protected void DatabaseType_SelectedIndexChanged(object sender, EventArgs e)
         {
-            toggleVisible(DatabaseServerItem, !ManualConnectionString && !IsEmbeddedDatabase);
-            toggleVisible(DatabaseUsernameItem, !ManualConnectionString && !IsEmbeddedDatabase);
-            toggleVisible(DatabasePasswordItem, !ManualConnectionString && !IsEmbeddedDatabase);
-            toggleVisible(DatabaseNameItem, !ManualConnectionString && !IsEmbeddedDatabase);
+            ToggleVisible(DatabaseServerItem, !ManualConnectionString && !IsEmbeddedDatabase);
+            ToggleVisible(DatabaseUsernameItem, !ManualConnectionString && !IsEmbeddedDatabase);
+            ToggleVisible(DatabasePasswordItem, !ManualConnectionString && !IsEmbeddedDatabase);
+            ToggleVisible(DatabaseNameItem, !ManualConnectionString && !IsEmbeddedDatabase);
 
             //toggleVisible(DatabaseConnectionString, ManualConnectionString);
         }
 
-        private static void toggleVisible(HtmlGenericControl div, bool visible)
+        private static void ToggleVisible(HtmlGenericControl div, bool visible)
         {
             if (!visible)
                 div.Attributes["style"] = "display: none;";