OK, things seem to have gone from bad to disaster. I seem to have lost all of my bookmarks. There are years and years of bookmarks that have been painstakingly organized and now they are gone.

It is becoming really obvious that people at Mozilla just do not care about the effort people put into collecting, organizing and managing their bookmarks. This support forum is a total joke because there just is no support. The whole sync feature is a really cruel hoax.

You should still have JSON backups in the bookmarkbackups folder that you can use to restore the bookmarks.
You may need to disable (unlink) the computer to avoid losing the bookmarks another time.

See "Restoring bookmarks from backup":

• http://kb.mozillazine.org/Backing_up_and_restoring_bookmarks_-_Firefox

I looked at the JSON backups, and they are all empty, which is when I realized this has escalated from a serious inconvenience to a full-blown disaster.

Any luck with trying to restore a previous version of either places.sqlite or an older JSON backup?

• http://windows.microsoft.com/en-US/windows7/Previous-versions-of-files-frequently-asked-questions

I'm in the same boat. This error has been popping up for a while and apparently long enough for the last good backups to be overwritten with nothing ...

My only hope now is to find a recent PC/VM backup that still contains all bookmarks.

I am not pleased to say the least.

Same problem here. All of my Firefox instances not only stopped syncing, but dropped all of my bookmarks, all at the same time. I actually had a browser open in Windows 7 when this happened, and noticed that at the same time the sync error first occurred, my bookmarks toolbar went completely blank. As soon as I noticed, I followed all of the recommended procedures, but all resulted in the same blank bookmarks, including downloading a third-party places management add-on that was recommended by Mozilla (which is strange, since they did'nt develop the add-on and could easily add adequate management themselves), but this does nothing to mitigate problems that have already occurred.

It's pretty frustrating in all. And to top it off, I can't get rid of the stupid sync failure notification in my Ubuntu Firefox browser, after performing all the recommended steps. Clearly _something_ must have changed recently?

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

You can 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

• bug 817445 - Bookmarks have disappeared and no new bookmarks can be created

(please do not comment in bug reports: https://bugzilla.mozilla.org/page.cgi?id=etiquette.html)

Thanks, but I'd already seen those suggestions and have tried them multiple times.