Firefox Community Forum

I transferred my FireFox files from my older model macbook pro to this macbook air (M3) and maintained/used the FF3/oes daily. I installed the latest update, Tahoe 26.7, before shutting down my computer last night and this morning I discovered that my FireFox windows and tabs had disappeared, completely. Can these files be recovered, and if so, what are the steps?

I am having an unusual problem with my main Firefox profile on Windows 10. The affected profile is:

C:\Users\Adam\AppData\Roaming\Mozilla\Firefox\Profiles\2giwv8i8.default-release-1746901618396

Firefox reports that this profile contains a user.js file. I cannot read, rename, move, modify or delete this user.js, even from an elevated Administrator CMD or PowerShell session. Attempts return “Access is denied.”

The unusual part is that Windows permissions appear correct. icacls shows my user account, SYSTEM and Administrators all have Full Control. The file is not encrypted, is not read-only, is not a reparse point, and Firefox is completely closed when I test it.

I also tested writing a new file directly into this Firefox profile directory and receive Access Denied. Other older Firefox profile directories on the same NTFS drive are writable, so the behaviour appears specific to certain Firefox profiles.

I have already performed a Firefox Refresh/reset, but the problem remains and user.js is still present.

I am investigating this because I am also experiencing unusual behaviour specifically with this main Firefox profile when using YouTube. Other Firefox profiles do not reproduce the same behaviour. I therefore want to completely eliminate any persistent profile configuration as a cause.

Can someone explain:

What could prevent access to an entire Firefox profile despite NTFS ACLs showing Full Control? Can Firefox, Firefox Sync, Enterprise Policies, an extension, or another Firefox mechanism protect or recreate user.js? Why would Firefox Refresh leave or recreate user.js? Is there an official/safe way to identify which preferences are being loaded from user.js when Windows itself refuses access to the file? Is there a way to reset all non-default preferences in this profile without losing bookmarks and saved passwords?

I can provide about:support, about:config, profiles.ini, ACL output and other diagnostics if required.

I would particularly appreciate advice on diagnosing why the profile directory itself returns Access Denied despite Full Control, rather than simply creating another profile, because I would like to identify the underlying cause.

Had to restore entire backup image of C: (boot) SSD that was saved on an external USB drive. I had been using FF 156, but the image restored FF 155. My FF profile is always stored on D: (internal HDD).

I launched FF and got a message that my profile was created with a newer version of FF and might not be compatible. The only option was to create a new profile or exit. I created a new profile but when FF opened I had no direct access to my existing profile on D: HDD. It wasn't listed when I clicked the Profiles button on the toolbar.

Came across a site that said to run Start>Run>firefox.exe - P. A box opened that listed both the newly created profile and my existing one on D: HDD. I selected the profile on D: and FF launched without any problems - everything fully restored. So if the existing profile is compatible, why was it so difficult to select it?

How 'bout this..? When FF detects that an existing profile was made with a newer FF version than currently running, why not give the user the option to install the latest FF update on that same message screen, in addition to the option to create a new profile? Then just relaunching FF after the update should allow an existing profile to be selected/used. Obviously existing profiles are compatible with FF updates since everything still works after routine updating.

Exact same thing happened with Thunderbird after reimaging C: because an older version was restored. I tried running thunderbird,exe -P without knowing if that would even work, and it easily allowed me to restore all 5 of my mailbox profiles with thousands of emails that are stored on D: in seconds.

Please make things easier...!

When I was running a game and updated my graphics card driver, Firefox was running in the background. My PC went completely black and became unresponsive, so I had to force‑restart the computer.

After rebooting, Firefox reverted to a brand‑new fresh‑install state. All my browser settings, login status, local profiles, browsing sessions, hundreds of open tabs and my categorized tab groups disappeared, only the welcome startup guide showed up.

I logged into my Mozilla account on my Android Firefox device. Some browsing history was synced back. However, synced history cannot restore the original tab session back‑forward page history, nor my manually sorted tab groups. All browser preferences, theme and language settings are also lost.

I originally had 4 separate local Firefox profiles on this Windows computer, isolated from each other for different work purposes. Only one profile was logged‑in to my Mozilla account and could partially sync data. The other three local profiles are completely gone. Those extra local profiles were NOT signed into any Mozilla account and were never synced to cloud storage.

In my Mozilla account’s connected devices list, there are two entries both belonging to this same computer: “MARSHAKK” and “Firefox by Administrator on MARSHAKK”, which correspond to my Firefox instance before and after the crash.

I cannot understand the community help articles about session recovery, and I’m unable to locate or restore my old local Firefox profiles and lost tab sessions by myself. Please give me assistance.

I had 5 tab groups and all of them vanished when I reopened my Mozilla today. I have tried to re access but all in vain, is there a fix on how I can regain my tab groups. I use windows 11

After problems with loading the current Firefox session, I seem to have retrieved my bookmarks (I cannot be certain all of them are there), except the Bookmarks toolbar and Other bookmarks folders are empty. I have a recent backup, but when I try to import the json file, it wipes out all bookmarks - I have to reboot to see them again. If I had them in html format I might try to manually add the missing bookmarks. Even better, maybe there is a way to merge the current and backed-up bookmarks. But I don't want to make things even worse. Any advice that certainly will work? Thank you for your help. Incidentally, sometimes the bookmarks won't load, and I have to reboot, sometimes several times, to see them again. How might I avoid this?

I use Firefox under Fedora (I'm two OS versions behind, must upgrade soon). I open very many tabs each day then work through them, theoretically every day, in practice they accumulate and I deal with them when I can. I rely on the tabs loading correctly on restart, but today they didn't, instead the set of tabs that were opened a few days ago loaded, and I lost everything I had done since then. Is there a way to retrieve the tabs that were opened just before this happened, ie around 15-20 hours ago? Ideally, again, I would merge them with the current ones, but reopening the old ones would take much much longer than reopening the new ones. Thank you for any advice.

Firefox is continually emptying my toolbar folders of bookmarks. I am forced to open "Help and Report," then choose "More Trouble Shooting Information" then open "Profile Folder" then close Firefox then select "Places.sqlite" delete it then restart Firefox and the folders are repopulated with the removed bookmarks. To date no one has offered any support. This happens multiple times per week. I cannot be the only one this is happening to. Someone please offer a permanent solution. I have removed then reinstalled Firefox a dozen times and the situations persists. I have a Win 11 Home OS

Thank you

Hello

This is a know old issue for me . That private session multi tab is gone. Nothing happened, I was these hour ago. I made changes setting to make work. Battery optimisations, defaultes to never close detete seassion. I am beyond angry fed. Please tell it's still there.

“Open previous windows and tabs” is on. History is set to Remember history. I do not close tabs one by one. Ctrl+Shift+Q sometimes restored 8 tabs, but closing with the X or Close and exit only opens the homepage. Restore Previous Session is missing. The 8 sites are not in History. I cannot find sessionstore.jsonlz4. Need help using sessionstore-backups.

I don't know how you can help. I would like to know how many other people are experiencing what I am, which is a repeated loss of all of my saved passwords. This has now occurred at least six or seven times over a several week span, on one computer (Business). Another computer (Home) I use is set to not auto update and that has not been effected. I believed I set the computer on which I am having difficulty to also not update, however the loss of passwords (all at once and entirely) keeps happening without effort or notice. This is driving me to contemplate changing the Browser I consistently use and have been satisfied with but if I can neither get help or otherwise find a solution there will be no alternative. The rebuilding of my saved password base is exhausting and frustrating and a complete waste of time and effort. I have written previously and asked for assistance and did get some lame try that went absolutely nowhere. I am admittedly not particularly computer savvy yet neither am I a novice. The communication via Mozzilla is not helpful as there are terms and phrases used that have no meaning for me so are near impossible to follow as result.

firefox just did an update now all my history has disappeared as have all my bookmarks. in addition I can no longer add bookmarks and my history is always empty. should I go to chrome or explorer or something else that may work

Nach dem letzten update ist alles anders. Gespeicherte Ordner,, Lesezeichen, gesamten Erscheinungsbild ist weg bzw. nicht schön. Ich möchte meine alte Version wieder zurück.

Update downloaded a few days ago, I closed Firefox to restart with updates and I can't get my previous session back. I even tried my OneTab to see if I could get older stuff back and it's lost that too!