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Sync encountered an error while syncing: Unknown error.

Posted

Bookmarks vanished on multiple computers.

Error message on all platforms: Sync encountered an error while syncing: Unknown error.

Android device seems unaffected. Attempts to re-sync good data from android device have no effect. I filed a bug report but after over 15 days it was marked as a duplicate and rolled into another bug report. The solutions there are way (WAY) beyond my technical level of expertise, and look to be for the unix OS. Something about a corrupt root.

I've been very reluctant to clear my sync data, because the impression I get is that I'll lose all my bookmarks. The entire reason I started using Sync was to back them up!

Computer1: Win7 enterprise sp1, 64bit. Firefox 17.0.1 Computer2: Win7 enterprise sp1, 64bit. Firefox 17.0.1 Android device: Dell Streak7 Android 3.2 Firefox 17.0

Chosen solution

Try to disconnect from Sync, quit Firefox, delete places.sqlite, restart Firefox, and re-set up Sync.

You can use this button to go to the Firefox profile folder:

  • Help > Troubleshooting Information > Profile Directory: Show Folder
Read this answer in context 5

Additional System Details

Application

  • User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20100101 Firefox/17.0

More Information

the-edmeister
  • Top 10 Contributor
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3197 solutions 24405 answers

Sorry you had a problem with Firefox Sync.

In no specific order.

  • Your first stop should have been this forum, not Bugzilla. Loss of user data isn't necessarily or always due to a "bug".
  • Firefox automatically backs up bookmarks daily on each PC or "desktop" version. Not sure about "mobile".
  • Then it is just a matter of restoring the previous days bookmarks backup, when bookmarks are "lost".
  • 10 days worth of backup files are saved before the oldest is overwritten.
  • Mobile device "sync" service isn't equal to "desktop".

If both of those Win7 PC's have been used with Firefox over 10 days each, the daily bookmark backups are gone. No sure what to recommend at this point.

cor-el
  • Top 10 Contributor
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10762 solutions 96861 answers

Helpful Reply

If you've lost bookmarks then you should make a backup copy of the JSON backups in the bookmarkbackups folder.


Problems with bookmarks and history not working properly can be caused by a corrupted places.sqlite database file.

You can check for problems with the places.sqlite database file in the Firefox Profile Folder.

Question owner

@the-edmeister: The main reason I submitted a bug report was because that's what the knowledge base pointed me at after I found zero information there about this issue. I only found this forum via a link from an outside forum post regarding this same issue but back in 2011.

@cor-el: That information is exactly the sort of thing that I needed! If only I had found out about it sooner.

FYI: Bug report filed 816840

From what I can tell my bookmark data is irrevocably lost at this point. There is a slight chance I may have an older instance of Firefox that I have not sync'ed since before this issue on an rarely used laptop. From what I can tell my only recourse is to purge the data on the Sync server and pray the data on the laptop isn't too old to be useful.

It seems rather strange to me that a service that touts itself on keeping your data safe would have such a critical flaw in the Sync service.

EDIT/UPDATE: deleting the data on the Sync servers has NOT corrected the issue. Still getting the message: Sync encountered an error while syncing: Unknown Error. Sync will automatically retry this action. Also, attempting to restore a JSON backup from before the sync issue started (courtesy of a windows backup over a month old) resulted in no bookmarks being restored.

Modified by merana33

cor-el
  • Top 10 Contributor
  • Moderator
10762 solutions 96861 answers

Chosen Solution

Try to disconnect from Sync, quit Firefox, delete places.sqlite, restart Firefox, and re-set up Sync.

You can use this button to go to the Firefox profile folder:

  • Help > Troubleshooting Information > Profile Directory: Show Folder
CalliedJ 0 solutions 1 answers

I've had this exact problem, and stumbled on a symptomatic solution. I unlinked my Android device from Firefox sync, and linked it again. All bookmarks from Android are now on my computers again, and are syncing. Hope this works for you too. This of course doesn't address the root cause of the problem, which is still unknown.