Firefox Sync uses the most recent version of the data. Try closing Firefox on all your devices, fix your bookmarks on one, then click the Sync button. When that's done, sync the rest of your devices. If this doesn't work, try fixing the bookmarks on all of the devices manually.

I fixed it. It turns out my iCloud bookmark sync with Firefox was 2-way syncing instead of 1-way like I thought. Somehow my bookmarks got duplicated 18-19 times in icloud and it was syncing those back to firefox.

moderator selected the solution to bring this thread to a marked conclusion

This problem has not been solved. For one, I have hundreds, maybe thousands of duplicate bookmarks that I do not want to touch because it would take ages to get rid of them. Second, it keeps duplicating. I'm highly frustrated with Mozilla for not fixing this since it's been going on for almost a year now. How come you people can't create a fix for this? And how come you guys have not made it so all the duplicates get deleted? When will this be fixed?

phoenix5,

Please start you own questions thread here: https://support.mozilla.org/en-US/questions/new

As evidenced by this thread, many times it is a result of user error. This thread the cause was another bookmarks sync being used in conjunction with Firefox Sync. In other seemingly similar threads, the cause was a corrupt places.sqlite file.

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

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