Firefox Community Forum

The question has been edited after doing further testing on the issue.

During the last week or so I have encountered the issue that one or more of my Firefox profiles keep resetting after every update.

I noticed there's couple of threads with similar issues already but the generic profile restore instructions are not helping at all since it seems that Firefox is actually wiping some files. I'm not currently sure what causes the files to be wiped, but it's either related to rebooting the PC or starting / closing Firefox. The file deletion also doesn't always hit the same profile either.

I'm running Firefox 150.0.1 for Arch on CachyOS.

I did a clean reinstall of Firefox. After the install I created 2 new accounts in addition to the one that's pre-created on install. All of the profiles work as expected at this point.

The profiles seem to have files in three places

• $HOME/.cache/mozilla/firefox
• $HOME/.config/mozilla/firefox
• /run/user/1000/psd/

The issue seems to be that after a reboot the files under /run/user/1000/psd/ are missing. Both of the other locations seemingly are unchanged but under $HOME/.config/mozilla/firefox the linked files claim no target in /run/user/1000/psd/ is found.

When looking at the missing files, it seems that in total 6 folders have been wiped at the time of testing. All of the wiped directories were ending as ".Profile 1" or ".default-release". Directories ending with ".Profile 2" or ".default" were still there. At this point I'm not sure what is causing this but it seems to explain why the profile is inaccessible.

Manually restoring the files under /psd/ seems to fix the missing profiles completely.

Hi,

My Firefox had auto updated to the newer version with AI built-in and auto-enabled, which meant the browser would crash EVERY. SINGLE. TIME. I would launch it.

For perspective, I am running an old Lenovo Thinkcentre mini PC with an Intel i5 6th gen and 16gb of ram; its got Windows 11 installed, and always running out of memory with the simple things like browsing and word processing. This is NOT a PC or use-case that needs or warrants AI.

So, I uninstalled Firefox (149) and installed the latest version WITHOUT AI built-in (147).

I then synced my profile, and things ran fine. An hour passed, and then i kept getting an error, saying my profile was created with whatever and I need to create a new profile.

So, I created a new profile and synced, again, and I got the error, AGAIN...

I'm about to boycott Firefox on all the devices I control, and opt for an older version of Opera or something more obscure, so that I don't have to deal with this nonsense.

I have a folder/subfolder, Old Firefox Data/ukn05f6l.default-release, on my desktop created 11/30/2024.

Any ideas what it is? It is huge...940mb.

Can I delete it?

Thanks

I'm a Chinese firefox user, so the following descriptions are translated and may not be so accurate. And the attached image is also Chinese, if necessary please use a translation app or somewhat to see it. I have only one default profile in my Firefox account, and I have stored a large number of passwords and bookmarks in this default profile. For certain reasons, I signed out of this profile while retaining the local data such as passwords—meaning that, apart from not being logged in, my browser state remains exactly the same as before. Now I wish to sign back in to enable synchronization. I can see a "Sync and Save Data" button prompting me to log in. After clicking this button, I am asked to enter my username and password, but then I receive a message stating that I have reached the account limit for this profile, and that this profile was previously synced to another account. This is absurd, as I do not have another account, nor have I ever synced this profile to any so-called other account. As a result, I am unable to sign in on this current profile.

I have an account for standard support release versions, I am now using extended support release version 140.7.0 and a popup notification keeps nagging me to make a new profile. How do I do this?

I just update firefox but all my none of my bookmarks loaded. I share my computer with my husband. He has a different account on this same computer and his bookmarks are showing up on my side, but mine are nowhere to be found. Previously we have had separate bookmark lists and all was fine. I don't know where my bookmarks went.

How do I get them back and put on "my side" and still have my husband's on his side?

I am trying to set up a profile however when I click the account icon the profiles menu item does not show up like it says on the manage firefox profiles guide. I am updated to latest firefox version.

I recently reinstalled Debian 13 on my workstation. This included installing Firefox-esr from the Debian repositories so the version before and after the reinstall is the same. Despite this, Firefox refused to start until I created a new profile - insisting that my profile was from an older version.

To add insult to injury, it offers a method to import data from Chromium (which I use rarely) but not from a previous Firefox profile.

Firefox Sync works so far as it goes, but not everyone wants to use it. Importing from a local profile should be easier to implement than remotely syncing - especially given that Firefox clients may not be the same on different devices.

And, of course, the initial point is that Firefox should accept a user profile when it was created by the same version. After all, when I upgrade Firefox on Debian, I'm not required to create a new profile. Why should I be forced to do it when I reinstall the same version?

I am using a very old system that is running out of storage space. There is an 8.73 GB folder that I would like to empty to free up space. C:\dtemp\Profiles contains several folders that were created 10.27.21: 2qzfs15q.default, eybandys.default, f81zrqic.default-release, pctnmazu.default-release-1, and yns5cb3s.default-release.

Can I delete any of these folders?

I created multiple profiles with the new [management] feature. Amazing, I've been waiting for it for years!

If I open all my profiles I can distinguish them since they all have a different icon. I can also pin all the profiles (Keep in Dock) to the MacOS dock.

When I quit all Firefox instances, I would like to be able to immediately jump back to the desired profile.

Instead I get multiple Firefox icons (without the icon profile, that disappear after I quit Firefox). I find this inconvenient.

I don't have a Profiles menu under the Account button on the main toolbar. My Firefox was just updated and the update tab info talked about the new profiles feature as if it was available. Is this rolling out in phases or should I be seeing it?

I have version 144.0, updated on 10/14/2025.

Thanks.

Hi - Firefox placed an 'Old Firefox data' folder on my desktop and I am unable to delete it. I'ver tried third party apps, logging in as administrator, command line delete, uninstalling FF but am still stuck with it and my network settings are wrecked so I can't re-establish connection to the internet on that machine. Anyone with any suggestions as to how I get rid of the 'Old Firtefox data' folder ? Many thanks...

I opened up Firefox just now to find that my two profiles currently in use are completely inaccessible. I was faced with a "Create Profile" dialogue that launched me into a brand new profile with none of my settings, keybinds, cookies, extensions, anything. Despite this, I know for a fact that my old profiles are *still* there. As you can see my profile folders are right there, with all their data intact as far as I can tell from inspecting their contents, yet they are not accessible from the about:profiles.

Please help me. What is happening with the profile manager? How do I access those old profiles?

Starting with Firefox 141, I noticed the profile folder is locked down by Mozilla by way of folder permissions, to the extent that I (as administrator) cannot even take ownership of the folder. Even after I completely uninstalled Firefox and restarted my computer I can't take ownership of the folder, nor can I delete it - access is simply denied. I have to literally boot up with a Linux Live distro to be able to delete it. This is invasive and NOT OK!!

I work with multiple profiles that require backups and be copied. I also have a 'master profile' which is set up to co contain all my settings and addons - when I require a new profile I simply copy it over and voila. Not even this is possible anymore, as Mozilla has locked down the entire folder tree, I can no longer copy a new profile into C:\Users\*USER*\AppData\Roaming\Mozilla\Firefox\Profiles.

I also cannot copy existing profiles (and therefore also not able to backup) out of C:\Users\*USER*\AppData\Roaming\Mozilla\Firefox\Profiles - access denied. This is uncalled for by Mozilla. I have complete removed Firefox from my computer, including registry entries, and even after that I'm still denied access and cannot even delete C:\Users\*USER*\AppData\Roaming\Mozilla.

The only solution to to any of the above issues is to either reboot into Windows Safe Mode or bootable media of another OS. But this is totally impractical - Mozilla cannot expect of me to stop all my work and restart my PC every time I need to perform any of the above mentioned issues.

This is highly invasive by Mozzilla - to not even be able to delete a profile folder without any trace of Mozilla on my computer???? Come on, FIX THIS !!!

Will Mozilla please provide the solution?