Error loading save, Invalid field id: 0, something went wrong in the stream

Saved server, restarted, now I get this error.

Error loading save (server/12409/proceduralmap.3666.1986311123.158.sav): Invalid field id: 0, something went wrong in the stream

Also:
NullReferenceException: Object reference not set to an instance of an object
at BuildingBlock.GetGrade (Enum iGrade) [0x00000] in <filename unknown>:0
at BuildingBlock.get_currentGrade () [0x00000] in <filename unknown>:0
at BuildingBlock.ChangeSkin () [0x00000] in <filename unknown>:0
at BuildingBlock.UpdateSkin (Boolean force) [0x00000] in <filename unknown>:0
at SaveRestore.InitializeEntityConditionals () [0x00000] in <filename unknown>:0
at Bootstrap+<StartServer>c__Iterator2.MoveNext () [0x00000] in <filename unknown>:0
at UnityEngine.SetupCoroutine.InvokeMoveNext (IEnumerator enumerator, IntPtr returnValueAddress) [0x00000] in <filename unknown>:0

(Filename: Line: -1)

 

I assumed as much. Thanks.