Does it still happen with all your extensions disabled?

I'm not using add-in tools and this has been a problem with Firefox for at least 8 years. We get the same tired responses that don't lead to a solution. Or the solutions are too complex and usually don't do anything. Why is Firefox doing this and when will THEY fix it and not give lame work-arounds that don't work?

Did you try disabling all your extensions?

Does it still happen when you are signed out of your Sync account?

Neither of those is a way I can use this product effectively and I don't have enough time in the day to troubleshoot for Mozilla. I'm not being paid to do that. Bring back proper QA, software engineers who are interested in resolution and solve the problem. This shouldn't fall on users and clever work-arounds disguising a good tech support. I've been using Firefox for decades and it's becoming a bloody mess. My career was computers and I retired as a software consultant. Something is terribly wrong here, and I'm reluctant to put things on forums because of responses like yours, zeroknight.

It could simply be one of your extensions misbehaving.

I highly doubt that. I have no extensions dealing with bookmarks or Firefox behavior. My hunches are unusually accurate because I used to write software. I know this is one of those bugs that Mozilla just won't fix. Like software everywhere these days.

An extension like default-bookmark-folder is known to cause issues when Firefox updates.

If you use Sync, best is to disconnect Sync temporarily during troubleshooting.

This could be a problem with the places.sqlite and favicons.sqlite files in the Firefox profile folder.

• use the "Places Database" -> "Verify Integrity" button on the "Help -> More Troubleshooting Information" (about:support) page

If errors are reported with "Verify Integrity", close and restart Firefox or reboot and retry.

If "Verify Integrity" cannot repair places.sqlite, rename/remove all places.sqlite and favicons.sqlite files in the Firefox profile folder with Firefox closed. Firefox will rebuild places.sqlite and restore the bookmarks from the most recent JSON backup in the bookmarkbackups folder.

• keep a backup copy of places.sqlite in case a new places.sqlite database has to be created
• you lose the history when a new places.sqlite is created

You may have to restore an older bookmarks backup in the bookmarkbackups folder via the Bookmarks Manager (Library).

• Bookmarks -> Manage Bookmarks -> Import & Backup -> Restore
• https://support.mozilla.org/en-US/kb/restore-bookmarks-from-backup-or-move-them

See also:

• https://support.mozilla.org/en-US/kb/fix-bookmarks-and-history-will-not-be-functional
• https://support.mozilla.org/en-US/kb/cant-add-change-or-save-bookmarks

You can use the button on the "Help -> More Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page (Root directory).

• Help -> More Troubleshooting Information -> Profile Folder/Directory:
  Windows: Open Folder; Linux: Open Directory; Mac: Show in Finder
• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

I don't have any of those kinds of extensions, cor-el. I did turn off Sync, so I'll see what happens. It's very time-consuming to try to delete all those bookmarks, only to have them come right back. I'll leave Sync off for now. Too much verbiage to read at the moment. I'm a busy man, have a lot of software, and all of them give links, links, links. I could easily spend an entire day reading all of them. Bring back tech support where they can look at our configurations and figure this stuff out. After all, they get paid to do that, where we don't.