Please view the accompanying video to learn how to purge your SharePoint application.
Purge and Start Over
If none of those options solve the sync issues, you’ll have to go nuclear. This involves not only stopping syncing any and all Document Libraries, but also clearing the system cache files before attempting to re-sync anything. First you’ll need to force-crash in the Task Manager any of the following background processes:
Then you’ll need to navigate in File Explorer and delete everything in the following locations:
For a Detailed View onTroubleshooting a Sharepoint Site, watch the accompanying Screencast.