This message has the following cause and solution:
When a Microsoft Access database is opened, the source code control provider tries to create a temporary working folder. If the folder already exists, the source code control provider tries to delete any files that might already exist in the folder. If any error occurs, this message appears. Note that the source code control provider silently deletes read-only files. One potential cause of this error is if the named file is a running executable file.
The working folder is for the exclusive use of the source code control provider. Do not attempt to store any files in this folder, or otherwise access this folder.