This weird! when I export my current bookmarks to html to a thumb drive, Firefox exports and old list, not the current list! I can add a bookmark, export the list, the new bookmark shows, but the list is not the current bookmarks. this new list contains bookmarks that I had deleted, and are not in my current bookmarks!
Is this how you are doing the export?
Open the Bookmarks Manager; Press the Alt or F10 key to bring up the toolbar, and select Bookmarks. Hot key is <Control> (Mac=<Command>) <Shift> B. Firefox 84+ <Control> (Mac=<Command>) <Shift> O.
Once the window is open, at the top of the page, press the button labeled Import and Backup. Select Export Bookmarks To HTML, and follow the prompts and save it to a HTML file.
If you use Sync then best is to disconnect Sync temporarily during troubleshooting.
This can be caused by a problem with the places.sqlite and favicons.sqlite databases in the Firefox profile folder.
- use "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 a 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 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.
- Help -> More Troubleshooting Information -> Profile Folder/Directory:
Windows: Open Folder; Linux: Open Directory; Mac: Show in Finder