Preventing Box Sync

Hi Robert, 

Welcome to the Box Community, I'm happy to help!

What determines the user's ability to Sync a folder to via Box Sync is their collaborator permission to a folder they joined. If a user has "Editor" access to a folder, they will be able to sync that folder to Box Sync. If you do not want collaborators to be able to sync your folders, I would suggest granting them with a lower permission level such as "Viewer Uploader or "Previewer Uploader"

For more information on this, please take a look at this article: Marking Content for Box Sync

Thanks for reaching out and if you have questions, please let us know!

Regards,