diff --git a/src/Umbraco.Core/Models/DataTypeDefinition.cs b/src/Umbraco.Core/Models/DataTypeDefinition.cs
index 4f2eb56b04..a56bbabf72 100644
--- a/src/Umbraco.Core/Models/DataTypeDefinition.cs
+++ b/src/Umbraco.Core/Models/DataTypeDefinition.cs
@@ -42,7 +42,6 @@ namespace Umbraco.Core.Models
         {
             _parentId = parentId;
             _propertyEditorAlias = propertyEditorAlias;
-            _additionalData = new Dictionary<string, object>();
         }
 
         private static readonly PropertyInfo NameSelector = ExpressionHelper.GetPropertyInfo<DataTypeDefinition, string>(x => x.Name);
diff --git a/src/umbraco.cms/businesslogic/Dictionary.cs b/src/umbraco.cms/businesslogic/Dictionary.cs
index 7a655f8373..e524f90429 100644
--- a/src/umbraco.cms/businesslogic/Dictionary.cs
+++ b/src/umbraco.cms/businesslogic/Dictionary.cs
@@ -2,8 +2,10 @@ using System;
 using System.Collections;
 using System.Collections.Concurrent;
 using System.Data;
+using System.Threading;
 using System.Xml;
 using System.Linq;
+using Umbraco.Core;
 using umbraco.cms.businesslogic.language;
 using umbraco.DataLayer;
 using umbraco.BusinessLogic;
@@ -19,7 +21,7 @@ namespace umbraco.cms.businesslogic
     public class Dictionary
     {
         private static volatile bool _cacheIsEnsured = false;
-        private static readonly object Locker = new object();
+        private static readonly ReaderWriterLockSlim Locker = new ReaderWriterLockSlim();
         private static readonly ConcurrentDictionary<string, DictionaryItem> DictionaryItems = new ConcurrentDictionary<string, DictionaryItem>();
         private static readonly Guid TopLevelParent = new Guid("41c7638d-f529-4bff-853e-59a0c2fb1bde");
 
@@ -33,30 +35,28 @@ namespace umbraco.cms.businesslogic
         /// </summary>
         private static void EnsureCache()
         {
-            if (!_cacheIsEnsured)
+            using (var lck = new UpgradeableReadLock(Locker))
             {
-                lock (Locker)
+                if (_cacheIsEnsured) return;
+                
+                lck.UpgradeToWriteLock();
+
+                using (var dr = SqlHelper.ExecuteReader("Select pk, id, [key], parent from cmsDictionary"))
                 {
-                    if (!_cacheIsEnsured)
+                    while (dr.Read())
                     {
-                        using (IRecordsReader dr = SqlHelper.ExecuteReader("Select pk, id, [key], parent from cmsDictionary"))
-                        {
-                            while (dr.Read())
-                            {
-                                //create new dictionaryitem object and put in cache
-                                var item = new DictionaryItem(dr.GetInt("pk"),
-                                    dr.GetString("key"),
-                                    dr.GetGuid("id"),
-                                    dr.GetGuid("parent"));
+                        //create new dictionaryitem object and put in cache
+                        var item = new DictionaryItem(dr.GetInt("pk"),
+                                                      dr.GetString("key"),
+                                                      dr.GetGuid("id"),
+                                                      dr.GetGuid("parent"));
 
-                                DictionaryItems.TryAdd(item.key, item);
-                            }
-                        }
-
-                        _cacheIsEnsured = true;
+                        DictionaryItems.TryAdd(item.key, item);
                     }
                 }
-            }
+
+                _cacheIsEnsured = true;
+            }            
         }
 
         /// <summary>
@@ -64,9 +64,12 @@ namespace umbraco.cms.businesslogic
         /// </summary>
         internal static void ClearCache()
         {
-            DictionaryItems.Clear();
-            //ensure the flag is reset so that EnsureCache will re-cache everything
-            _cacheIsEnsured = false;
+            using (new WriteLock(Locker))
+            {
+                DictionaryItems.Clear();
+                //ensure the flag is reset so that EnsureCache will re-cache everything
+                _cacheIsEnsured = false;
+            }
         }
 
         /// <summary>
diff --git a/src/umbraco.providers/members/MembersMembershipProvider.cs b/src/umbraco.providers/members/MembersMembershipProvider.cs
index 2e906d7f8d..9f6297554c 100644
--- a/src/umbraco.providers/members/MembersMembershipProvider.cs
+++ b/src/umbraco.providers/members/MembersMembershipProvider.cs
@@ -792,7 +792,7 @@ namespace umbraco.providers.members
 
             return null;
         }
-
+        
         private static string GetMemberProperty(IMember m, string propertyAlias, bool isBool)
         {
             if (!String.IsNullOrEmpty(propertyAlias))
@@ -1081,6 +1081,7 @@ namespace umbraco.providers.members
                   DateTime.Now, DateTime.Now, DateTime.Now);
             }
         }
+
         #endregion
     }
 }
diff --git a/src/umbraco.sln b/src/umbraco.sln
index 52550c6365..728c643afc 100644
--- a/src/umbraco.sln
+++ b/src/umbraco.sln
@@ -1,7 +1,5 @@
 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio 2013
-VisualStudioVersion = 12.0.20827.3
-MinimumVisualStudioVersion = 10.0.40219.1
+# Visual Studio 2012
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Build", "Build", "{2849E9D4-3B4E-40A3-A309-F3CB4F0E125F}"
 	ProjectSection(SolutionItems) = preProject
 		..\build\Build.bat = ..\build\Build.bat
@@ -177,4 +175,7 @@ Global
 		{73529637-28F5-419C-A6BB-D094E39DE614} = {DD32977B-EF54-475B-9A1B-B97A502C6E58}
 		{B555AAE6-0F56-442F-AC9F-EF497DB38DE7} = {DD32977B-EF54-475B-9A1B-B97A502C6E58}
 	EndGlobalSection
+	GlobalSection(Performance) = preSolution
+		HasPerformanceSessions = true
+	EndGlobalSection
 EndGlobal