Diễn đàn hỗ trợ Firefox

Hello,

My little brother signed me out of my mozilla account while trying to login to his school account using my computer yesterday. Now, even after signing his account out AND removing his account entirely from my firefox, I'm unable to login using my credentials on the "original profile" which is what I've always used. This is the message I get when trying to login:

This profile was previously synced to a different account To keep your data organized and secure, each Firefox profile can only be synced to one account. To sign in using (email)@gmail.com, create a new profile.

He wasn't even able to fully login with his account, and even after completely removing his account from my firefox (as far as I know) I'm not able to sign into the original profile at *all*, even though that's what I've always used. Does anyone have a solution for this?

When I try to login with my Firefox account to configure Sync, I get a message that says that I am logged on to a different profile and asks if I want to switch. If I switch, I get the same result with the other profile. There is only one profile folder in the Profiles directory, there are no other files or folders. What should I do?

I've been using the extension "Tree Style Tab" and "TST Colored Tabs." I've been looking for a way to disable the native Firefox tab bar, whether on top of the window or to the left side. I haven't been successful on my own.

After a couple of hours troubleshooting this with CoPilot, It suggested I post the following short summary:

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Firefox 152.0.6 (64-bit) about:profiles shows active profile: C:\Users\dmerc\AppData\Roaming\Mozilla\Firefox\Profiles\usm8kxcr.default-release

Opening that directory from about:support shows an empty folder.

profiles.ini references: agwp164m.default-release

userChrome.css loads correctly in a separate profile but not in the profile containing my current extensions and history.

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The details of how it came to this conclusion:

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Based on everything you've found:

The profile with your current extensions and recent history is reported as: usm8kxcr.default-release

Opening that profile folder shows an empty directory. The only other real profile on disk is: agwp164m.default-release

We successfully proved userChrome.css loads in a different test profile (Profile 1) because the toolbar turned red. Therefore, the CSS mechanism itself works on your machine.

My conclusion is that your Firefox profile registration has become inconsistent. Firefox appears to be using a profile that does not correspond cleanly to the profile folders you're seeing in Explorer. At this point I would:

Back up the entire folder: (NOTE: DONE - backed to to another drive) C:\Users\dmerc\AppData\Roaming\Mozilla\Firefox

Keep using the profile that contains your extensions and recent history. Avoid deleting any profiles or profile folders.

Post the details you've collected to either: the Mozilla Support forum, or r/firefox

The key facts to provide are: Firefox 152.0.6 (64-bit)about:profiles shows active profile: C:\Users\dmerc\AppData\Roaming\Mozilla\Firefox\Profiles\usm8kxcr.default-release.

Opening that directory from about:support shows an empty folder.

profiles.ini references: agwp164m.default-release

userChrome.css loads correctly in a separate profile but not in the profile containing my current extensions and history. \ Those facts point to a profile-management issue rather than a Tree Style Tab or CSS issue.

The good news is that your current extensions and recent history are still accessible, so this doesn't look like data loss. The profile mapping itself needs to be untangled before custom CSS can reliably be applied.

=

It also suggested not copying any folders and files between profiles for now.

Or to open the profile selection sidebar?

I don't see it in about:keyboard but maybe there's something else somewhere.

If not, what's the quickest and easiest way to switch profiles?

I created a new profile on my account. Whenever I am in the original profile, I can click on the new profile and it will open a new window with a new icon. However, I notice that under the new profile, it is not signed in. When I try to sign in, I get an error that says

Account already in use xxx@gmail.com is already signed in to the “original” profile

You can only associate this account with one profile on this computer.

Then it forces me to switch back to the original profile. This tells me that the profile is not syncing for access across devices.

This is happening on my macbook.

i have been with Firefox since it started and now you have changed it to the pint where i am leaving it . i want my original profile i do not want any old profiles where i lose everything like bookmarks and everything i have added extensions you forced me to leave to leave unless i can keep the old profile always see you Firefox you have just forced me to go to chrome thanks a lot unless i can keep the old profile original prpofile and still update the versions as need ed other wise good bye to you

I recently opened this 'bug' which may involve my inadvertent use/misuse of Profiles. https://bugzilla.mozilla.org/show_bug.cgi?id=2052294

How can I locate other (older) Profiles in the Mozilla Firefox structure and use this to run an older version of Firefox ie: 132 or other Version that I consider to be more stable.

(I have already seen where it is not recommended to go to an older version, once a profile has been used on an updated version. At this time - I feel any damage has ALREADY been done & cannot make things much worse.)

When I try to edit a profile (name, color theme), about:editprofile returns a blank page.

It was working just a few minutes ago, but stopped while I was trying to select a new theme.

I've restarted the browser a couple of times and looked at help articles but cannot figure out how to fix it.

I thought original profile would save all my bookmarks, history, passwords, etc. I created a second profile for work, but that also does not contain any of my bookmarks, history, passwords, etc. I imported my bookmarks and other history/passwords from EDGE. I did this in my work profile because I couldn't get my original profile to import anything. I signed into work with my main firefox e-mail and exported bookmarks to HTML so I could upload it in my original profile. The original profile now wont log in and says I need a different e-mail account, so I'll lose everything on my original profile. It is ridiculous that my profiles don't have the same log on and don't use the same e-mail. I need someone to help me recover my system to normal working function. This has been a horrible experience and profiles are unusable.

Hey all,

at shell:startup on windows i will open firefox two times (first for multimedia like tv-stream and maston, second for "working activities" like webmail, office online).

How can i open by file explorer link (like in shell:startup) a new tab (newspaper) everytime in instance "first" even if i was using second at last?

I had a problem where FF 140.0 would not update, and in trying to get FF yo update, I used a re-install tool to which I was pointed in my problem report. This caused FF to wipe out my configuration, and I lost all my windows and tabs. I have gone to

    \Appdata\Roaming\Mozilla\Firefox\Proifiles\abnfpged.default

cleared all of the data therein, and restored that directory from a backup I made last Monday. But I cannot get FF to use that directory. "about:profiles" shows only two profiles, but the Profiles directory has five profiles:

03/10/2026 09:39 AM <DIR> qf00ka5x.default 03/10/2026 09:39 AM <DIR> v842ceue.default-release 04/11/2026 09:16 PM <DIR> .. 04/11/2026 09:16 PM <DIR> . 04/12/2026 03:08 PM <DIR> abnfpged.default 04/12/2026 06:29 PM <DIR> jdfj91sd.default-release-1775960183850 04/12/2026 06:48 PM <DIR> f1jq4mlq.default

Only the profiles beginning with "j" and "f1" are seen in the "about:profiles" screenshot I have attached. And I have attached a screenshot of my profiles.ini file. Also, in the abnfpged.default directory I restored, where is the list of all of my open windows and tabs? FF used to keep that in a sessionstore.jsonlz4 file, but that file is only written when FF closes. I tried to save a copy when I was having problems, but I stored the copy in the same directory, which FF changed during the re-install process. Here is my profiles,.ini file:

[Install308046B0AF4A39CB] Default=Profiles/jdfj91sd.default-release-1775960183850 Locked=1

[Profile1] Name=default IsRelative=1 Path=Profiles/f1jq4mlq.default

[Profile0] Name=default-release IsRelative=1 Path=Profiles/jdfj91sd.default-release-1775960183850

[Install641D10338ABA448D] Default=Profiles/abnfpged.default Default=1 IsRelative=1 Locked=1

[General]

StartWithLastProfile=1

Version=2

[BackgroundTasksProfiles] MozillaBackgroundTask-308046B0AF4A39CB-defaultagent=lnvi5jn5.MozillaBackgroundTask-308046B0AF4A39CB-defaultagent

I have not worked with the ;profiles.ini file in many years, as my FF configuration has not had problems. 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.

Updated to FF 150 today on Win 11 desktop.

Q1: Can I remove Profiles from the FF toolbar which is located in between Bookmarks and Tools? Only need one profile on this PC. I tried to customize the toolbar but it won't let me drag Profiles off.

Q2: For some reason my FF profile is now on C: even though I had previously moved it to D: to free up space on C: boot drive.

So I created a new profile with exact same folder name on my D: drive today.

In Profile Manager, I renamed the old profile on C: to "name.old and the new one on D: to "name.new". I set name.new as the default profile and it works properly after exiting and restarting FF.

Now I want to delete the .old profile but FF won't left me, saying Can’t delete a profile that is linked to other profiles. There are only the .old and .new profiles listed. So how do I unlink .old so I can delete all of it to free up space on C: ?

Yes, I'd like to use the same account on both of my profiles.

I understand that for some users, this may be confusing.

In my case, the only reason for different profiles is that I need to use a Proxy Server for some websites, and no proxy for other websites. Manually switching proxy settings is painful, and doing so causes traffic for my other tabs/windows to go to the proxy, which I do not want.

I have a main (set of) windows (and its tabs) going straight to the internet, then I have a separate window (and its tabs) configured to go through a proxy (SOCKS5 in this case). I want all other settings, bookmarks, passwords, etc. to be identical to both. I end up having to logout of my main profile, log into the other profile to sync settings, log out of there, and log back into my main profile.

Is there a valid technical reason why an account on the same FireFox installation cannot be shared between two profiles?

I can do this on multiple computers (same account, different computers/profile), seems odd it is restricted to not allow on the same computer.

I have an alternative solution: Install FireFox natively, then install FireFox as AUR or FlatPak, but not sure this will collide as this both uses the same profile directory. Hum...

Wayne