Hello Yollyej,

You can try the following,

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.

These can't get your data back, but will help in the future.

These add-ons can be a great help by backing up and restoring Firefox

FEBE (Firefox Environment Backup Extension) {web link} FEBE allows you to quickly and easily backup your Firefox extensions, history, passwords, and more. In fact, it goes beyond just backing up -- It will actually rebuild your saved files individually into installable .xpi files. It will also make backups of files that you choose.

OPIE {web link} Import/Export extension preferences

Do you have an "Old Firefox Data" folder on the desktop in case you have used the Refresh feature in Firefox and have created a new profile?

Thank you for your help and explained possiblities! Second one is ok, but for the future, so I've lost 20 years of bookmarks etc., home and job ones, pretty bad. I know that my account was hacked on 16th December, so I thought that MOzilla has some kind of backup and could restore it from their side and possibly have logs from where it was done, what is the most important thing in order to stop criminals.

Please reply if any of written above is possible. Thank You either way!

Have you blocked the hacker? Found out who?

You evidently didn't read the first answer, by sotos, too well. "Firefox automatically creates backups of your bookmarks, ..."

YES, Firefox does save backups of your bookmarks saved right inside of your Firefox Profile folder, but with the "loss" occurring on Dec 16 and asking for help on Jan11 - you may be outside the window of 15 saved backup files. So if you have used Firefox more than 15 days since that happened, all you'll find is 15 (basically) empty files. Open the "Library" windows as sotos instructed and view your backups. See if you still have a backup that is "time stamped" before your discovery of your loss.