Hi Gustav,
Are you using shared network drive to host you Revit file? Or do you have shared network drive otherwise in use?
I have noticed that using shared network addresses with Tekla BIMsight project sharing is not a good thing as those drives are not accessible all the time. Windows hides that issue from the UI, but as software is not waiting the UI it runs into issues. Same situation could be happening here.
Best regards,
Marko Myllymaa