Value cannot be null. Parameter name: stream

I apologize for the incorrect date above. This was fixed in october and should roll out in the November release of desktop. 

Till then, as a workaround, you can try doing

File -> Options and settings -> Options -> Data Load (under global) -> Folded artifacts cache options -> clear cache

This should clear and regenrate the cache. (the error occurs when trying to read the cache.)

thanks

Rahul