Firefox Community Forum

I run the current Firefox version under Windows 11 Pro on a Dell Inspiron 15 3530 laptop, Lately, I've been having problems with my bookmarks:

• First, I found that I had somehow lost a large number of bookmark tags; it took me several days to restore them,
• Next, I found that I had lost a bunch of bookmark subfolders; the bookmarks (for the most part) are still listed under their tags.
• When I try searching for tags in Bookmarks Manager, the search yield no results
• When I try to restore my bookmarks from a previous date, I get an "unable to process file" message.
• When I try to open the profile folder through the debugging information page, I get a "file not found" message. After some searching, I found the profile folder not at "C:\Users\croge\AppData\Roaming\Mozilla\Firefox\Profiles\7csymh5k.default-release", but at "C:\Users\croge\AppData\Local\Packages\Mozilla.Firefox_n80bbvh6b1yt2\LocalCache\Roaming\Mozilla\Firefox\Profiles", Something seems to have gone haywire--did I miss something, or is there an error somewhere?

This is the message I get when I try to access my Bookmarks: "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 already tried to find out from Microsoft if their latest reinstallation of Office Professional could have caused the problem. They say they have nothing to do with Firefox. How can I get my Bookmarks and History back?

Several times now I've closed firefox while having the open previous windows and tabs on startup on only for all my tabs to have been closed (with this time in particular being annoying due to losing tabs that I needed to have the specific link for). Is there any way to restore tabs lost in this way?

Firefox updated. I know no longer have access to my bookmarks, saved links, and passwords. How do I revert back to previous version of Firefox? How do I retrieve access to my passwords, bookmarks, and saved links/pages? I will need easy step by step instructions.

Any assistance would be greatly appreciated.

Thank you.

I updated Firefox to 145.0 this morning, and after Firefox had restarted, it had lost all bookmarks and the bookmarks toolbar. I have spent all day following links to correct the problem and got nowhere. I have restarted Windows and Firefox countless times - no change. I've even tried reinstalling Firefox over the existing version. If I go to bookmarks > manage bookmarks > restore and backup, sometimes that will load, others not. When it does load, it fails to find a file to restore from. 10 years of bookmarks, links & research vanished.

Can someone please provide a solution (preferably in Layman's terms) to this??

Firefox updated automatically. No bookmarks or history??? I cannot find anything. This is my old Windows 10 computer. Have bookmarks on Windows 11 computer. Afraid of updates. any help?

I have no idea what happened, but i was changing settings on my PC and suddenly i was logged out and all my browser data, bookmarks, passwords etc were gone. I dont know if i clicked the wrong button or what but everything is gone. I still have my data on my phone, and can access my passwords and such but I dont know how to get the browser data from my phone onto my PC

Please, I have many important passwords and bookmarks that I need to be able to recover.

I think that this recent update removed all of my tabs and tab windows, it has done this before and I don't understand why, I have the old update session file still (The 11/11/2025 One) and I tried to use that one to bring the tabs back by putting the file in the sessionstore-backup folder with no other file in it, but they didn't come back. I am genuinely confused as to why it doesn't work, I have renamed and deleted sessionstore.jsonzl4 files but it still comes up as a new session.

Does anyone know how to restore a previous profile? I had a situation like this: I had Firefox 140. I decided to upgrade to 147. Then I upgraded to 145 and all my data disappeared. The system is Linux Ubuntu.

Hello there, today was released a new version of firefox. downloading it not only crashed my computer, it also removed all my history and bookmarks. is there any way to revert this?

Can Firefox do anything to recover all of the downloads I'd saved until I accidentally had CCleaner erase everything? I don't know what else was deleted, but getting them back would be a big help.

Using firefox 144 on Kubuntu 24 LTS, on wayland, with Nvidia drivers.

I'm one of those guys with 500+ tabs. I also have a bunch of tabs open in specific containers and I recently spent a lot of time sorting most of my hundreds of tabs into a bunch of neat tab groups.

I'm not using any "sync between devices" functionnality

At some point, I open firefox like usual, and I noticed that it appears to be glitched. The rightmost tab (the last tab I had opened) seems to be working fine, but every other tab has no text, and I cannot switch to them. However, the colored line indicating that a tab is opened in a specific container still appears, it's just the tabs names that are missing. Also, firefox seems to generally not be responding, so I decide to close and reopen it.

Upon reopening, firefox restores my tabs, but I'm left with only the last tab I mentionned earlier. The "restore last session" button doesn't appear in "history". Neither "recently closed windows" nor "recently closed tabs" contain my 500+ tabs

I still have my extensions

I still have my bookmarks

I still have my base "new tab" setup, with my background image and my "pinned" websites (I don't know how it's called)

I still have my container "rules" (i.e, firefox still proposes to open specific domains with specific containers, even if I have lost old tabs that were opened in those containers)

I still have my "auto sign-ins" (i.e, I can still log into some websites without re-typing my password)

I have lost my tab groups

I'm used to losing my tabs. So I close firefox, and I go look in it's files.

The image firefox-mpris in the files still displays a youtube tab I was watching (yet this tab doesn't get restored)

I make a copy of sessionstore.jsonlz4 and sessionstore-backup, and try restoring from each backup by replacing sessionstore.jsonlz4 :

- the default sessionstore.jsonlz4 doesn't have my tabs of course

- previous.jsonlz4 has only the single last tab I mentionned earlier.

- recovery.jsonlz4 contains only 20-ish of some of the most recent tabs I had

- the "upgrade" files contains a bunch of tabs but it's from a few months ago so I'm missing the most recent stuff

Using this "scrounger" tool, I can look at what these files contain

https://www.jeffersonscher.com/ffu/scrounger.html

- sessionstore.jsonlz4 and previous.jsonlz4 both contain the single tab we talked about before (plus closed windows I don't care about)

- recovery.jsonlz4 contains exactly 25 recently opened tabs (plus closed windows I don't care about)

- upgrade.jsonlz4 contains 500+ tabs (with container ids, yay), but not the most recent ones of course (plus closed windows I don't care about)

From I saw online it looks like firefox only stores the last 25 tabs in these files, which are the last tabs I actually opened, even if more actually exist. What I really don't understand is : - Why does my upgrade.jsonlz4 file have more than 25 tabs then ? - Where are the other tabs supposed to be stored then ? the .jsonlz4 stores the last 25 tabs, yet firefox (usually) remembers all my 500+ tabs anyway, so where are they stored ?

Also, y'know, pls help me restore my stuff. Thanks.

Hi, I'll try to explain exhaustively my problem and what I've tried.

While looking at adding a new profile, I made a mistake and deleted the actual profile. Firefox immediately shut, and I made the mistake to open it right after...

It started from zero, as it had no profile to go into. Creating a new profile in the same time. I did this a few time, nothing changed obviously. I went to the AppData/Roaming path to find my old profile, which wasn't there anymore. I then managed to recover my profile files thanks to Recuva and EaseUS.

But now, I'm stuck. When adding the files in the newly created profile, it seems to roll back to the profile creation prompt (like import stuff from other browsers etc.). Copy/pasting only the desired sessionstore or the previous backup doesn't work either. It also tried to put the "good profile" in the Profiles folder. Firefox didn't recognize it, and I couldn't create a new profile from this folder in the Profile Manager as it said "this name is already used" etc. (it's a default-release) I then tried to edit the profiles.ini and install.ini to force Firefox on the wanted profile. Which succeeded and failed at the same time: it opened the right profile-folder, but without any session, bookmark... and back again to the profile creation prompt. And created a new empty sessionstore, prefs, etc.

Then I'm left with my recovered backup files and no idea how to import them...

Any help will be warmly welcomed! Cheers

Something very bad happened to me today (11/3)....

Firefox 144.0.2 was installed on 10/30/25, and everything has been fine until today. I don't know why or how, but ALL of my OPEN tabs (of which I have many--and have it fixed so they always re-open when Firefox starts), ALL went away.

In reading conventional steps to recover such from sessionstore-backups, those instructions sounded straightforward. However, even though ALL FIREFOX PROCESSES were ended, I could not copy the contents of the sessionstore-backups folder nor could I delete anything--EVEN THOUGH I am the owner.

Even after providing Admin perms.

I could get rid of profiles.ini, which initially proved diasterous, because then Firefox thought I was brand new, so ALL of my passwords saved through Firefox these many years, went "poof".

Fortunately, I was able to get that back, but I still cannot get all of my tabs back, and conventional instructions to do so aren't working.

After recovering from my heart attack for initially losing my passwords, I am breathing a little better right now, but it sure would be nice to get all of my open tabs back again. I don't know why I am not able to manipulate the files within sessionstore-backups. I think if I could eliminate the files in that folder EXCEPT for upgrade.jsonlz4-20251027123126, which possesses a 10/29/25 date, these should be the open tabs just before the 144.0.2 installation, and all should be right with the world, once more.

I have performed/examined many steps offered under this category, but most assume I can copy them elsewhere for safe-keeping and/or removing all but the one I want Firefox to "use". Because something is preventing me from doing this, though, I am being stymied in what ought to be the solution. As a test, I was able to copy files from a much older profile--so I can prove the basic steps SHOULD HAVE worked. Unfortunately, I cannot do the same with THE (more recent) folder in question. I can't get rid of parent.lock, either (and I have ensured no Firefox processes are running via Task Manager).

Repeatedly.

Something else is at work, here. Any help or assistance from community experts would be most helpful.

Thanks very much in advance.

-MG

The launch of Firefox Profiles seems to have obliterated everything in my account: bookmarks, history, open tabs, and extensions are all gone completely. I have an option to import files from another browser, but not from my own past firefox. I logged into my Mozilla account, but I didn't have any other devices so I think it was still unable to recover the data? Is there anything I can do about this, or is all of my data truly gone?