Originally Posted by
Steve_Stafford
Someone on your team used the Rollback feature, they saved the project to an earlier version. That means any local files that are based on the more recent version are no longer able to synchronise. That is logical. How could Revit reconcile changes between a newer version and an older version.
The rollback feature should never be used without letting the entire team know about it and nobody should be working on the file when/while it happens. Once it is done they all need to create new local files.