diff --git a/src/Orchard/Environment/Extensions/ExtensionLoaderCoordinator.cs b/src/Orchard/Environment/Extensions/ExtensionLoaderCoordinator.cs
index 964dbb6a5..8cc499a13 100644
--- a/src/Orchard/Environment/Extensions/ExtensionLoaderCoordinator.cs
+++ b/src/Orchard/Environment/Extensions/ExtensionLoaderCoordinator.cs
@@ -87,14 +87,14 @@ namespace Orchard.Environment.Extensions {
 
         private string GetExtensionHash(ExtensionLoadingContext context, DependencyDescriptor dependencyDescriptor) {
             var hash = new Hash();
-            hash.AddString(dependencyDescriptor.Name);
+            hash.AddStringInvariant(dependencyDescriptor.Name);
 
             foreach (var virtualpathDependency in context.ProcessedExtensions[dependencyDescriptor.Name].VirtualPathDependencies) {
                 hash.AddDateTime(GetVirtualPathModificationTimeUtc(context.VirtualPathModficationDates, virtualpathDependency));
             }
 
             foreach (var reference in dependencyDescriptor.References) {
-                hash.AddString(reference.Name);
+                hash.AddStringInvariant(reference.Name);
                 hash.AddString(reference.LoaderName);
                 hash.AddDateTime(GetVirtualPathModificationTimeUtc(context.VirtualPathModficationDates, reference.VirtualPath));
             }
diff --git a/src/Orchard/Utility/Hash.cs b/src/Orchard/Utility/Hash.cs
index dacfead52..7cfa01c10 100644
--- a/src/Orchard/Utility/Hash.cs
+++ b/src/Orchard/Utility/Hash.cs
@@ -10,12 +10,28 @@ namespace Orchard.Utility {
     public class Hash {
         private long _hash;
 
-        public string Value { get { return _hash.ToString("x", CultureInfo.InvariantCulture); } }
+        public string Value {
+            get {
+                return _hash.ToString("x", CultureInfo.InvariantCulture);
+            }
+        }
+
+        public override string ToString() {
+            return Value;
+        }
 
         public void AddString(string value) {
             if (string.IsNullOrEmpty(value))
                 return;
-            _hash += value.GetHashCode();
+
+            _hash += GetStringHashCode(value);
+        }
+
+        public void AddStringInvariant(string value) {
+            if (string.IsNullOrEmpty(value))
+                return;
+
+            AddString(value.ToLowerInvariant());
         }
 
         public void AddTypeReference(Type type) {
@@ -24,7 +40,22 @@ namespace Orchard.Utility {
         }
 
         public void AddDateTime(DateTime dateTime) {
-            _hash += dateTime.ToUniversalTime().ToBinary();
+            _hash += dateTime.ToBinary();
+        }
+
+        /// <summary>
+        /// We need a custom string hash code function, because .NET string.GetHashCode()
+        /// function is not guaranteed to be constant across multiple executions.
+        /// </summary>
+        private static long GetStringHashCode(string s) {
+            unchecked {
+                long result = 352654597L;
+                foreach (var ch in s) {
+                    long h = ch.GetHashCode();
+                    result = result + (h << 27) + h;
+                }
+                return result;
+            }
         }
     }
 }