"cannot move file" in Unity 5.5 beta collab

I keep getting this “cannot move file” error in collab. How do I fix it so I can update the project?


I’m getting this in 5.50b6 – seems there’s a semi-recent thread here:

The workaround is to, unfortunately, delete (backup) your project and re-download it. Mine is 10gb, which is a bit depressing, but still occurring in 5.50b6. Maybe the newer beta fixed it? But I’m not sure.