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Good Afternoon,

I am enjoying the easier profile management with the new profile system, and I am using it currently for splitting personal / work usage. I was just wondering if it is possible to set 'Choose a profile when Firefox opens' to always apply when running a Firefox shortcut, not just when Firefox is not currently running (similar to Chrome's 'New Window' option)?

Thanks, Robert

I got a message on my Win10 PC saying, "Your Firefox profile can not be loaded. It may be missing or inaccessible."

Mozilla help suggests looking in %APPDATA%\Mozilla\Firefox\Profiles\. I did this but don't know what to do next.

I have another Win10 PC where Mozilla still works, and they do sync. Should I copy some of the Mozilla folders from it to the first PC to restore the problem? Which ones?

BTW, I can still run the Mozilla TOR Browser on the first PC. Thank you!

If I'm not mistaken, between FF146 and FF147 it appears the location of the profile directory has changed. It was:

   /home/<user>/.mozilla/firefox  

and now is

   /home/<user>/.config/mozilla/firefox

Is that correct?

I recently upgraded Thunderbird from v140.7-ESR to v147-Release and would be grateful if someone could answer some questions.

After upgrading I noticed there are 3 profile folders even though I am the only user of my Win11 laptop.

Profile Folders 92yfgi88.default-esr - 3.654 GB - 2026/01/23 12:50:27 >> My profile jf63jfuk.default-default - 1.533 GB - 2024/06/05 21:27:32 y9efj7q9.default - 47 Byte - 2026/01/23 12:30:15

The folder y9efj7q9.default only contains 2 files - parent.lock (0kb) and times.json (1kb).

1. Can I safely delete profiles I don't use?

2. Why is -ESR still shown at end of my profile folder name? - I thought it would be renamed when I changed to the release channel version.

3. Can I manually rename my profile folder? - I know I can rename a profile using Profile Manager but this doesn't rename the folder.

4. If not possible to rename my "92yfgi88.default-esr" folder, I assume I can just copy it's contents to another new profile folder and tell TBird to start using that?

5. Can I use Windows File Explorer to delete/rename profiles, or must this be done from within Thunderbird?

Also, any idea why Thunderbird Notifications still show as coming from Mozilla Thunderbird ESR, even though I now use the Release version? I've checked Windows 11 System > Notifications and it is still shown there as Mozilla Thunderbird ESR.. Why? and how to fix?

Thanks in advance..

As the title says, when i go to about:support, and click the open profile folder, i wanted to install a customization to allow me to edit the default tab background, but for some reason i do not have admin privileges in that folder, i can't access anything, i can't edit anything nor create a new folder, even rename it. It says that my own computer does not have admin privileges inside that folder.

I have two personal Thunderbird accounts that were under two other email addresses on an old computer. They are [email1] @mlecwb.net and [email2] @mlecwb.net

Can I access them another way, since that computer is not working well enough to download emails? Plus the old email addresses will be disappearing with the the company l have the email addresses under.....

Then if I can get into the old messages, can I download and save some of the messages - or at least important ones in specific group files - onto another computer or a laptop? Or even on a CD?

Also, could I still use Thunderbird under another email address?

Susan Clark Harris [email3] @outlook.com

today I tried using a link from discord to go to a site. a window I was unfamiliar with stating it was firefox told me to pick a profile. I had 2 at that point but I saw none at that point. I ignored it and did nothing. I restarted my computer later on after a file browser issue and when I tried to find my profiles and my last session I found nothing. my entire fire fox account has been wiped and I only have a single profile in my app data thats onlder than 2026. I have no idea whats happened.

I tried to transfer my Thunderbird e-mail account to a new Laptop. I followed the instructions for using an external harddrive. I copied my profile , connected the external harddrive to the new device and filled my profile in. But actually I don't find Thunderbird e-mail in the taskbar and I can't access to it. What do I have to do?

Hi, I am having a problem with the recently introduced Firefox profile system. In the Windows taskbar, different profiles stay grouped under the same icon. The only workaround I found is going into taskbar settings and setting it to 'Never combine,' but that causes every program to show text labels, which looks ugly. I also tried modifying taskbar.grouping.use_profile in about:config, but it didn't solve anything

I’m running into a limitation with Firefox profiles involving the original Profile Manager (about:profiles) and the new Profiles menu in the toolbar.

I previously created multiple profiles using the original Profile Manager (about:profiles), for example profiles A, B, and C. These profiles still function normally and can be launched through about:profiles, but they do not appear in the new Profiles menu in the toolbar.

I also tried using the “Copy this profile” option available from the new Profiles menu. This made it clear that the feature does not work with profiles created via about:profiles. For example, when I open profile A, I expected that I could use “Copy this profile” to copy profile A into an existing profile like profile B (which was also created using about:profiles). However, this is not possible. Profiles A, B, and C remain isolated from the new Profiles menu and cannot be accessed, copied, or managed through it.

At the moment, profiles created with the original Profile Manager (about:profiles) can only be accessed through that manager and cannot be transferred into the new Profiles menu in the toolbar.

Is there an official fix or a workaround that achieves the same result—specifically, transferring or integrating all existing profiles created with the original Profile Manager (about:profiles) into the new Profiles menu accessible from the Firefox toolbar?

I keep receiving the following pop-up. How do I get rid of it?

Pop up: This profile was last used with a newer version of this application. Please create a new profile

I use Thunderbird 115.18.0 on a Windows 7 machine. I wish to transfer all my Thunderbird data to a machine running Linux Mint 21.3 which has Thunderbird 128.12.0esr. I have not been successful after many tries. Could this be because the Thunderbird revisions are different? If so, can I get 115.18.0 to install on my Mint machine? If not how should I proceed? I have already tried creating a new .thunderbird directory with ********.default directory from the other machine. I have also tried a new .thunderbird directory with a the ********default-release directory as directed by one site.

Just lately, Firefox has been going on about Profiles, I don't know why. I have no need for such things, yet in my Windows menu, everything says "– Original profile" at the end. All this does is make things difficult to see. How can I get rid of it, please?

Hi, So I used Thunderbird to create a zipped backup file of my profile. I got the warning that if the file size if more than 2 GB I may want to make a manual backup. I proceeded, and ended up with a file that was 15 GB. I then uninstalled Thunderbird, reinstalled it, and tried to import my backup file. Thunderbird gave an error, saying the file is too large, and I should manually extract it. Okay, I tried, but Windows 11 failed to extract the file. I then used a third-party app to extract the files. This gave me a c2140ucr.default folder that contained three direct subfolders and many, many files. I located my inbox.ca file, which is what I really want, but I cannot find a way to import it into Thunderbird using the Tools menu. Any ideas on how to recover my previous profile would be appreciated. Thanks.