Thunderbird Community Forum

Hi, I have been using TB for many years, when suddenly 4 days ago ( Feb. 1st.) it started as a brand new install, asking to set up a new account, I got no previous warnings or had other issues.

Since then I have done several attempts to get it connected with my profile, among others: - Everything from this article https://support.mozilla.org/en-US/kb/profiles-where-thunderbird-stores-user-data - Importing the Profile from Functions > Import > "Import from another Thunderbird installation" - Reinstalling TB ( without removing the profile)

All of it with no succes, there is no accounts, and no mails, only some empty local folders so I'm running out of good ideas, and I really hope you can help!

BTW, somehow the addressbook has content, as the only thing.

Thanks Best regards Preben

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..

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

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, 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.

Hello, I just enabled the backup sync option for the Firefox web browser (Win 10). What is the equivalent process, or recommended method of enabling a backup for mail folders, calendar entries, address books, settings, etc. of the most current Thunderbird version on a Win 10 PC? I could not find a clear answer in the help forums. Thank you.

We are unable to sign in to thunderburd

using correct crudentials. We wen to geek squad to correct this issue. He installed webnet as a work around.

He said we would not lose any thunderbird emails however all the new and saved emails are no longer available to see or open. We would like you to reinstall thunderbird and restore all the lost emails. How does this get resolved?

I moved to a new PC and copied my thunderbird profile for my emails. I do not have access to my old PC at the moment. Is there any way to "log out" or disable the emails on the other PC by deleting the thunderbird profile access or similar?

I could go manually through google to log them out, but it will also remove the access on the new PC and in this situation there are a lot of accounts and the setup is a hassle.

Hi, In profiles, I have several, many of which are up to date and 2 are large, one which is meant to be my current profile at about 2.5 Gb and another at 3.6 Gb (plus others of about 50 Mb) - see screenshot. What is going on?

I tried to start Thunderbird and it would not open. There was a message that read, "Your Thunderbird profile cannot be loaded. It may be missing or inaccessible." After trying to fix it and nothing worked, I uninstalled and reinstalled Thunderbird. Now all of my contacts and data is gone. When I tried to use the import tool I selected import from another Thunderbird installation and I can't get past the continue button.

How do I recover all of my data and contacts/addresses?

Hi, how can we identify the version of a profile in order to know the appropriate version of TB ?

I am receiving a message that a newer version have modify my profile and i need the old version but it's no longer on my HD...

Thanks

I'm abandoning Windoze for Linux Mint Mate. The original Win11 Laptop is still available - no cloud connection, the Windows account exists but is unused. The laptop has all my Thunderbird v146.0.0 (64 bit) mail, address books, calendars.

I have a refurbished PC, came with new-install Win11. Now dual-booted as a Linux Mint 22.2, Mate desktop. The Win11 partition is unused and will stay that way for the foreseeable future.

I use gmail since TalkTalk finally terminated access to my Tiscali account. (I dropped TT many years ago.)

I've setup Thunderbird on Mint, can't see how to find its version. It came from the Mint default setups. Gmail is working but missing all the 'Local' stuff. The calendar has a few of my auto-repeat entries but none of the random ones. Some of my address books are missing.

I remember from the Win10 > Win11 migration that I need to move the 'profile'. It will be large but I have big-enough USB memory keys. And no, the machines are not network linked. I don't trust Microsoft and won't allow any of their corrupted stuff any access to my new kit.

Guidance needed:

• What needs to be moved? From where on Win11?
• Where to put the stuff on Mint. How to migrate it?
• Any problems to watch out for?

Help please? Links to resources? Forum posts, online guides, wise words? Or 'just do it this way!'

TIA PeteS

Hello. Today, gone through updates from 115.10.1 to 115.18.0 to 128.14.0 to now 140.6.0 and still cannot shut down Thunderbird in one profile, to then be offered a choice of profile and changeover. It just would not today do that. Instead it re-opens in the original profile, without the profile selection box. Any solutions? Thanks.

My old Windows10 computer died, but I have an external backup with my Thunderbird profile folder. In the meantime, I have been able to resurrect an old Windows10 computer to continue receiving email, but was not successful transferring the backup profile. Thus, I have "new" profile on this second computer containing only the recent emails not in the backup profile.

I've purchased a new Windows11 computer. My question is: How can I merge my old emails in the backup profile with the recent emails received after the backup was made? In other words, is it possible to merge two separate profiles into one? Thanks.

Illinichip

Oct 23, 2025, 19:35 CST

I FINALLY was able to find the original profile, all messages in the In Box, plus all folders with their contents. 'Lost' when our ISP's ' tech support person ' had me close/remove the TB POP3 account and create an IMAP account).

I need to merge the new small profile (In Box & with basic folders) into - onto the BIG, original, profile. So each time I get/check mail everything goes to, ends up in, the Thunderbird account containing all the OLD data and new working account.

Please remember I am barely TB literate, so start at 1 (A), not 27 (Z)& no tech words. Nor acronyms please.

Thanks! Remain in GOOD health, be WELL, 'n be

• • SAFE!**

Robin

My Windows 11 laptop became corrupted and the os had to be reinstalled with Microsoft's help. In the midst of all this I did not think of backups sadly. After the restore I started to put my apps back on and without thinking, I installed Thunderbird. I realized immediately my mistake when I saw only new email and no local folders.

The Windows restore created a windows.old directory and I see my profile and configuration files in it. I want to use those old files but I don't know where to copy them exactly. There is some confusion on my part about where the startup is happening for Thunderbird. I really need to have access to all my old mail and local folders.

I'd appreciate any help in this matter. Thanks, Sue