Could not load type 'UnityEngine.OffMeshLink' from assembly

I'm getting this error after upgrading my version of Unity for my project, and I can't figure out what to do to fix it, or pinpoint where it's coming from..
System.TypeLoadException: Could not load type 'UnityEngine.OffMeshLink' from assembly 'UnityEngine, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null'.
UnityEditor.EditorAssembliesrocessInitializeOnLoadAttributes()

I've searched for anybody else with this problem and can't find any clues. I did a grep through my project assets for OffMeshLink and couldn't find any direct references to let me know where it's being called, so possibly in a dll or something I'm missing. I'm still able to build to most platforms despite the error, although my Android build crashes immediately when ran, could be because of this. Hope someone has an idea for a fix.. Thanks.

 

same here