Hello,

Firefox automatically creates backups of your bookmarks, which can be helpful if your bookmarks are lost or missing. To recover them, follow the instructions below.

1. Use one of these methods to open the Bookmarks Library window:
   • Firefox 29 and above: Click the Bookmarks button and select Show All Bookmarks.
   • Previous Firefox versions: Click the Firefox button and click on Bookmarks. (If you don't have a Firefox button, click the Bookmarks button or Bookmarks menu item and select Show All Bookmarks.)
2. At the top of the Library window, click on Import and Backup and select Restore.
3. Click the date of the bookmark backup you want to recover.
4. In the new window that appears, click OK.
5. Your bookmarks from the selected date should now be restored.

For more information, see the Restore bookmarks from backup or move them to another computer article. For other solutions, see the Recover lost or missing Bookmarks article.

Did this fix your problems? Please report back to us!

Thank you.

Where did the old bookmarks come from and how did you transfer them to Firefox?

One thing you can try if bookmarks are missing is;

These instructions are for Firefox. These instructions will combine the new bookmarks with the old.

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.

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. Copy the file to another computer. Repeat the instructions above, BUT select Import Bookmarks From HTML.

https://support.mozilla.org/en-US/kb/restore-bookmarks-from-backup-or-move-them

https://support.mozilla.org/en-US/kb/recover-lost-or-missing-bookmarks