seems to have randomly moved bookmarks and/or folders and placed them in 'unsorted', and then deleted or hidden unsorted. Must have taken some coding, I'm impressed.

This happened to me immediately after I upgraded to version 1.6 of Sync. I managed to stop it before it messed up the bookmarks on all my machines, but it is totally unacceptable. I'm turning off Sync and going back to Xmarks.

■ Act quickly, recent versions of firefox save snapshot auto bookmarks for the situation as it was, by default, on the last five days. But do not act in haste read the notes first, otherwise you will be in danger of overwriting sets you want and loosing them

1. Make a manual backup of current bookmarks, (do this in turn for each device or profile) and keep the file somewhere safe. see Restore bookmarks from backup or move them to another computer but do Not use the restore option given their yet, that will just overwrite and loose a potentialy usefull set of bookmarks
2. Find and copy each of the auto bookmark files they will end in .JSON give each file a meaningfull name you can reimport them into firefox at some later date to examine and work on them

■ Look at

• Recover lost or missing Bookmarks especially - restoring bookmark backups
• and the article it is based on http://kb.mozillazine.org/Lost_bookmarks note that explains where files are and the possibility od saving whole profiles

I have firefox 3.6.13 and 4.0.Beta8 but I created a separate profile for the beta, so it has its own bookmarks, and if I consider syncing I think I will be creating yet more profiles

Make a backup copy of all the JSON backups in the bookmarkbackups folder in the Firefox Profile Folder elsewhere to prevent losing any backups that still have your lost bookmarks.

Thanks. It turns out I was able to restore a backup of my bookmarks via the "organize bookmarks" feature and selecting "restore." I was lucky because I had not added any important bookmarks since the most recent restore point. After doing this, everything went back and functioned properly. I am still nervous about Firefox Sync, but I'll keep using it unless it does this again. Thanks to everyone for the responses!

Ok, so it happened again. Firefox Sync scrambled all of my bookmarks at work. I think there must be a bug in Firefox Sync. For now, I'm moving back to XMarks. Sorry Firefox Sync.

Thanks for your answer, John99. I just took the first aid measures you suggested. And bumped the number of backup copies (browser.bookmarks.max_backups in about:config) to a value significantly more important than the default five, too.

Is there a way to browse the various automatic backup files with something similar to "organize bookmark" (other than restoring one copy after the other) in order to decide which one is the latest good copy?

TIA!

All I can say is thank God for Apple's 'Time Machine', I had to go back to the 23rd Dec this morning to find a clean version of the .json file. I have also done as filofel said and bumped up the number of backup copies to 20, to give me a bigger safety net within Firefox.

If it does it again I will check out XMarks that others have mensioned, although I also use Firefox Sync on the iPhone and iPad.

@ filofel

I have not tried opening the .json autobackups within firefox, but I think it can be done, and given that you are interested mainly in determining whether the file is corrupt or not I can think of a few potential ways to attempt checking this.

■ Text file - They are basically text files so open in a word processor, possibly after renaming them, maybe write and run a macro to display them correctly

■ Auto export on exit as html

• you can set firefox to export the bookmarks on exit as HTML
• see http://kb.mozillazine.org/Mozilla_Suite_:_FAQs_:_Bookmarks
• it may be reasonable to presume if the html is not corrupt the .json of matching dates will be ok
• the folder of the html exported files may be bookmarked and the files opened directly as firefox tabs

■ Ask on the MozzilaZine forum

• I note they have an old thread explaining how .json backups can be opened in firefox, with short JavaScript used to extract printable list of URLs
• see http://forums.mozillazine.org/viewtopic.php?p=5565535#p5565535
• that may not answer your question, but at least such matters are on topic and discussed over on MozzilaZine. ( I guess they are on topic here if as a solution to ongoing problems)

This is good information. As I had the corruption problem three times with Firefox Sync, I opted to remove it and go back to using XMarks (now owned by LastPass). Since going back to XMarks, everything has been smooth sailing.

As a side note, I also opted to use LastPass for a complete password manager. With LastPass and XMarks under one roof, both offering free versions and both seemingly working well together, I'm going to see how this configuration works out for now. This gives me all of my passwords and bookmarks across all platforms and browsers in a (hopefully) secure manner.

I will look into "upping" the number of backups Firefox makes just as a precaution.

txaaa i've stopped using firefox sync, this messing with my bookmarks gets extremely old fast >_< i cant work good if my bookmarks are all over the place...

Yes,I also had scrambled bookmarks,and I don't know what caused it.I have FF 8,and a couple of days ago,my bookmarks were suddenly scrambled.Thank goodness I have Xmarks on a laptop.I signed into my Xmarks account,and was able to sync my laptop bookmarks (which are almost identical to my desktop bookmarks) with my desktop bookmarks.I can't say enough good things about Xmarks.