Basically stop using Sync removing all devices and start again with a new email address. Note if you sync all the devices on the old service before you start a new one you are less likely to have problems. Also note the advice about still backing up your profile. In particular if you use Sync to Sync bookmarks I personally would take the precaution of backing them up on the main computer on a regular basis maybe every month because Sync can have issues occaisionally and could baddly corupt your Bookmarks. See * https://support.mozilla.org/products/firefox/sync ** [[How do I set up Sync on my computer?]] * [[Restore bookmarks from backup or move them to another computer]]