Disconnect that device from the Sync server like this:

Options > Sync tab --> below the "Device Name" use the Unlink This Device

Overall, it sounds like you have some data corruption between your devices as far as the Sync service goes, and it keeps propagating. My advice is to Unlink all your devices from Sync while you are trying to fix them, and use them for a few days to make sure they are all stable while not being connected to Sync. When you do want to re-enable Sync, make sure you create a new Password at the Firefox Accounts website, to clear your data from the Sync server before you re-connect the first device. (Or just create a new Sync Account to start from scratch) When adding additional devices to Sync, you should use Firefox for a couple of days on each device to make sure everything is actually synchronized before introducing the next device to the "ring" (actually it's a "star" with the server in the middle).

You can also check for problems with the places.sqlite database file in the Firefox profile folder.

• http://kb.mozillazine.org/Bookmarks_history_and_toolbar_buttons_not_working_-_Firefox
• https://support.mozilla.org/kb/Bookmarks+not+saved#w_fix-the-bookmarks-file

• Places Maintenance: https://addons.mozilla.org/firefox/addon/places-maintenance/