diff --git a/RecodeItGUI/GUI/Main.cs b/RecodeItGUI/GUI/Main.cs
index 761eef2..01be27c 100644
--- a/RecodeItGUI/GUI/Main.cs
+++ b/RecodeItGUI/GUI/Main.cs
@@ -41,7 +41,7 @@ public partial class ReCodeItForm : Form
         LoadMappingFile();
 
         var remaps = AppSettings.Remapper.UseProjectMappings
-           ? CrossCompiler.ActiveProject.RemapModels
+           ? CrossCompiler.ActiveProject?.RemapModels
            : DataProvider.Remaps;
 
         ReloadRemapTreeView(remaps);
@@ -1319,11 +1319,16 @@ public partial class ReCodeItForm : Form
     /// Subscribes the the remappers OnComplete event
     /// </summary>
     /// <param name="remaps"></param>
-    private void ReloadRemapTreeView(List<RemapModel> remaps)
+    private void ReloadRemapTreeView(List<RemapModel>? remaps)
     {
         RemapTreeView.Nodes.Clear();
         RemapNodes.Clear();
 
+        if (remaps is null)
+        {
+            return;
+        }
+
         foreach (var remap in remaps)
         {
             RemapTreeView.Nodes.Add(GUIHelpers.GenerateTreeNode(remap, this));
diff --git a/RecodeItLib/Remapper/RenameHelper.cs b/RecodeItLib/Remapper/RenameHelper.cs
index da1e7cd..cdbd833 100644
--- a/RecodeItLib/Remapper/RenameHelper.cs
+++ b/RecodeItLib/Remapper/RenameHelper.cs
@@ -1,5 +1,5 @@
 using Mono.Cecil;
-using Mono.Collections.Generic;
+using Mono.Cecil.Rocks;
 using ReCodeIt.Models;
 using ReCodeIt.Utils;
 
@@ -15,7 +15,7 @@ internal static class RenameHelper
     /// <param name="score"></param>
     public static void RenameAll(ScoringModel score, bool direct = false)
     {
-        var types = DataProvider.ModuleDefinition.Types;
+        var types = DataProvider.ModuleDefinition.GetAllTypes();
 
         // Rename all fields and properties first
         if (DataProvider.Settings.Remapper.MappingSettings.RenameFields)
@@ -60,7 +60,7 @@ internal static class RenameHelper
     public static int RenameAllFields(
         string oldTypeName,
         string newTypeName,
-        Collection<TypeDefinition> typesToCheck,
+        IEnumerable<TypeDefinition> typesToCheck,
         int overAllCount = 0)
     {
         foreach (var type in typesToCheck)
@@ -108,7 +108,7 @@ internal static class RenameHelper
     public static int RenameAllProperties(
         string oldTypeName,
         string newTypeName,
-        Collection<TypeDefinition> typesToCheck,
+        IEnumerable<TypeDefinition> typesToCheck,
         int overAllCount = 0)
     {
         foreach (var type in typesToCheck)
@@ -157,7 +157,7 @@ internal static class RenameHelper
         return propertyCount > 0 ? $"{newName}_{propertyCount}" : newName;
     }
 
-    private static void RenameType(Collection<TypeDefinition> typesToCheck, ScoringModel score)
+    private static void RenameType(IEnumerable<TypeDefinition> typesToCheck, ScoringModel score)
     {
         foreach (var type in typesToCheck)
         {