[SOLVED] Sims 4 Studio 1.3.4.2 (Apple Blossom)

Help please...

This morning I created a new mesh in blender and was able to import it into S4S with no issues. I close s4s and return hours later with a new mesh.


I go through the usual process of selecting the sims item (left ring) I want to use as a reference to attach my new mesh to and this is the message I receive... 

Sims 4 Studio 1.3.4.2 (Apple Blossom)
System.NullReferenceException: Object reference not set to an instance of an object
at S4Studio.Core.CloneEngine.CloneCatalogResource[T] (S4Studio.Data.IResourceProvider game_files, S4Studio.Data.IO.Locale.IStringTableCache global_stbl, S4Studio.Data.IO.Package.IDBPFPackage result, System.UInt64 instance, System.String hash_salt, S4Studio.Shared.CloneRenumberOption renumber_option, System.Boolean include_variant_thumb, S4Studio.Settings settings) [0x00071] in <6f064ec3ebe048448397ea60b2ecded2>:0
at S4Studio.ViewModels.CAS.CASPrototype.Clone (S4Studio.Data.IO.Package.IDBPFPackage p, S4Studio.Shared.CloneRenumberOption create_cas_option, System.String hash_salt) [0x00017] in <6f064ec3ebe048448397ea60b2ecded2>:0
at S4Studio.Shared.CASFeatureViewModel.Clone (S4Studio.Data.IO.Package.IDBPFPackage package, System.String hash, System.Collections.Generic.IEnumerable`1[T] selected_prototypes) [0x00026] in <6f064ec3ebe048448397ea60b2ecded2>:0
at S4Studio.Shared.FeatureViewModel+<>c__DisplayClass28_0.<CreateItem>b__0 () [0x00016] in <6f064ec3ebe048448397ea60b2ecded2>:0
at S4S.UI.Core.S4SWindow+<>c__DisplayClass11_0.<BeginLoading>b__1 () [0x00014] in <6f064ec3ebe048448397ea60b2ecded2>:0


Totally lost, thank you in advance