Firefox Community Forum

I was positively surprised recently when the new Firefox profile manager (about:profilemanager) was introduced. https://www.tech2geek.net/how-to-use-the-new-updated-profile-manager-in-firefox-2025/ is an article about that.

However, I thought it's just a new visual UI with an in-browser switcher for the existing profiles (that I already had setup). However, it does not appear so.

The differences I see:

1. 1. 1. old profile management

• was managed by `about:profiles` or when starting FIrefox with `-P`
• is saved in `~/firefox` and the `profiles.ini` clearly and quite obviously mentions them there, so it's easy to manage them.

I also found this old support article: https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles

1. 1. 1. new profile management

• automatically asks on startup if more than one profile exists
• is managed by `about:profilemanager` or with the Firefox burger menu
• seems to be saved in `~/.mozilla/firefox/Profile Groups` (Linux path here) in some .sqlite files, and I do not quite understand the format. Not mentioned in `profiles.ini`.
• also, when you change something here (even like opening a profile?), you cannot open `about:profiles` anymore, because it says "Some Firefox process has made changes to your profile, […] you need to restart Firefox", only after a restart further changes would be possible, which I find quite confusing but it also indicates somehow the features belong together?

And this seems to be the new one: https://support.mozilla.org/en-US/kb/profile-management#w_whats-the-difference-between-profiles-and-multi-account-containers

1. 1. Questions

• What are the differences here (I may have missed)?
• How can the new profile feature save so few files? Is it technically called "profile groups"?
• And the most important: How can I migrate an old profile? (In order to use the new features and GUI etc. I quite like)

Firefox version 145.0 in Linux Ubuntu 22.04.5 LTS. When I open Firefox all tabs from previous session are gone. On "Startup" I have checked "Open previous windows and tabs". Which worked before but not now. It is very frustrating. How do I fix? The Profile Manager opens the settings and "Open previous windows and tabs" is checked. Checking "ask before closing multiple tabs" doesn't help.

Recently upgraded to version 146.0 on Linux (Mint, Cinnamon)

YouTube will work fine when I first start the browser. Eventually videos will stop displaying and sidebar links will not be active.

From a separate forum article I cleared all site data and restarted Firefox. That fixes the problem for about 4 or 5 videos, then you need to rinse/repeat.

The latest incident seems to have been triggered when I tried to watch a video embedded in an X (Twitter) post. That failed. And the YT failed as a whole. X was open in a separate tab container at the time.

While I have both Privacy Badger and uBlock Origin installed, both are deactivated for YouTube.

See the attached images. The video is just not displaying, though the screen is reserving space for the player.

Both/all videos I have tested do work in Chromium.

I had so many instances of firefox and tabs that i decided i must organize them on tabgroups, i read they were secure enough and would be restored along with open tabs on new session. But after restarting all my "close and save" tab groups are missing! are they still saved? how can i recover them?

Selecting "Help About Firefox" causes the window to appear but this window then freezes with no information. It is possible to close the window and continue with Firefox. This happen nearly always but occasionally works correctly. Current Firefox version is 146.0 but the problem is not limited this version. System is Kubuntu 24.04, KDE Plasma Version 5.27.12 and QT Version 5.15.13 I have tried several things. Deleting the .Moziila folder will permit the window to work once but after a restart stops working. Any new things to try would be appreciated.

Hi Mozilla I hav got a problem with Firefox on Kubuntu 24.04.3. Everytime the computer is restarted Firefox crashes the first time it's started. That's not a big problem, starting Firefox again don't take long. But the problems is exceeding. If i start Firefox by clicking a link in a mail in Thunderbird. And Firefox has not yet been started, It crashes, but now it's also invaliding the Task bar on the screen where Firefox was started. Invaliding means that I cannot start apps from that screens taskbar, and the clock has stalled, none of the tools works etc. The only possibility solution I have been able to figure out, is restart (It's like going back to Win 98). Sometimes I am able to start a app from that invalid taskbar. But it's not the one app that i clicked on. Even though I can trigger it via Thunderbird, the invaliding of the taskbar will occur after a while. And I have to restart. I am not sure if this is the right place to post. But Firefox is always involved, but maybe Thunderbird or Ubuntu was the right place? Every time Firefox crashes there is send a crash report to Mozilla, but is has been going on for a while, so i guess that nobody is looking at the crash report. If I use Chromium instead of Firefox I don't see the problem.

Hello again guys,

when I play a video in Firefox, it doesn't keep the screen on.

I need this accessibility feature.

This happens, at least, with Debian 12's Firefox (uptodate), like over 1 year now.

Please help with that too.

Thanks in advance!

Regards from Germany, Johannes

Good day,

when I click in Instagram in the notifications on a comment, I get redirected to to the comment section, but not to that certain comment, so I would have to scroll a lot.

Please help with that.

Thanks a lot!

I will contact Instagram about that now too, as maybe the issue is on their side, or on your side.

Regards from Germany, Johannes

I can not open : www.mobile.de What is here going wrong ??

Access denied  ?? I cannot understand this ?? Thanks for help, rainer banspach