Firefox Community Forum

As of yesterday, Oct. 14, 2025, everything in my Firefox Bookmarks and History is gone. This is the message displayed: "The bookmarks and history system will not be functional because one of Firefox's files is in use by another application. Some security software can cause this problem." I have tried to recover them by different suggested means, but it would appear there is NOTHING to recover. Everything in Bookmarks says EMPTY, and I can no longer save any new Bookmarks, it just not allowed. How and why did this happen, and what am I supposed to do? I had hundreds of things Bookmarked, many of them were important to how I run my business, and now are seemingly all gone. This is very upsetting and would appreciate Mozilla getting this straighten out. I need and explanation and resolution.

Hi, All of a sudden, I lost absolutely all of my bookmarks. My PC is running Windows 11. My Firefox account was and still is logged in. At first, I thought the data loss was due to a CCleaner cleanup using their latest update. After the data was lost, I tried running another CCleaner cleanup, but this time it didn’t delete the bookmarks. So I honestly have no idea how this could have happened. These were bookmarks I had saved over many years... It’s a disaster.

PLZ Help

I upgraded to Firefox 143.0.4 and lost all of my Bookmarks. How do I find and reload my Default Profile? Also, I cannot load anything in Firefox I am forced to use Edge which I do not like at all!!!!

Fedora froze and I had to reset my PC. Firefox hat quite a number of tabs open wich are still visible in history Recently closed tabs. When I click there on Reopen all tabs nothing happens.

How do I open all recently closed tabs?

On my linux system, I have two users. If I log in as user A and use FF and leave a bunch of tabs open, I can view those tabs again later if I restart my computer and log in as user A, so FF remembers its history.

No Problem Scenario Logged in as A - open FF - open a bunch of tabs - CLOSE FF log out of A log in as B - do stuff log out of B log in as A - open FF; all the tabs are there

Problem Scenario Logged in as A - open FF - open a bunch of tabs - leave FF open (don't close FF before...) log out of A log in as B - do stuff log out of B log in as A - open FF; all the tabs are GONE

If I run into the Problem Scenario, I can sometimes use these steps to get the history/tabs back. https://support.mozilla.org/en-US/kb/how-restore-browsing-session-backup

Whether the steps work or not, the Problem Scenario is annoying. I don't know what causes this. My desktop manager is KDE.