Forum der Gemeinschaft Thunderbird

After Windows installed an update in the middle of the night I can't open Thunderbird and I've tried uninstalling it and reinstalling with success.

It says: Thunderbird is already running, but is not responding. The old Thunderbird process must be closed to open a new window.

I've rebooted the PC, shut down the PC, ended the task and still nothing. It seem that Thunderbird didn't shut down correctly and the system still thinks that it's open and running. Anyone know how I can fix this issue?

Thanks,

Gregg

Running Thunderbird 140.5.0esr

This has been happening for a few weeks now somewhat randomly. The folders under Mail for one of my accounts keep moving around and are not in alphabetical order anymore. Most folders are OK, but a few either jump to the top of bottom of the list. I can manually drag them back, only for different folders to do it the next time.

The folders in questions are 2 levels down from Mail.

Hello, I recently cleaned up my mail account and deleted obsolete folders on one device. The folder has been deleted on the server, but Thunderbird on another computer still shows the folder. In the subscribe menu the folder is not shown. But when I try to delete it it throws an error "The current command did not succeed. The mail server for account <account name> responded: [NONEXISTENT] unknown source folder.". The error makes sense since the folder has been deleted on the server. Is there a way to tell Thunderbird to just remove this folder?

Thanks in advance!

Hello,

I created an event in the Thunderbird calendar, inluded 30 e-mail addresses of which only 19 calendar invites were sent. It sent the invites in the order of the recipient list and just stopped at number 19..

What could be the problem here?

Thunderbird version 140.5.0esr on Ubuntu.

Forwarded emails contain no signature, either above or below the forwarded email body.

No means exists in settings to specify that a signature should be in forwarded emails.

Thunderbird resists configuration for included signatures specified in the configuration editor.

Is there a reason that settings, such as columns, layout, ordering, folder colours, etc. are not retained in the msf itself?

I have to use multiple machines, so tend to have an archive that I share across them as the primary storage of emails. However, nothing is retained between machines which is a bit annoying when trying to colour code for easy visual cues. So it seems clear that this information is currently stored in the local profile, even though the archive data is a filesystem.

Hi, I am using Thunderbird on my Android phone and PC. When I send emails from my Android phone, the emails are sent but a copy is not stored in the "SENT" folder of my phone. This feature used to work in the past, but now it doesn't anymore.

How can I resolve this? Thank you.

Today filtering of new emails fails for all folders. The message is "The message could not be filtered to folder <folder> because adding a message to it failed. Verify that the folder is displaying properly or try to repair it from the folder properties."

This is new. No problem filtering message a few days ago.

Windows 10 laptop PC.

Lots of free space on my local drive where Thunderbird is installed.

Where are these folders stored? I looked in C:\Program Files\Mozilla Thunderbird but I do not see any such folders there. I looked in C:\ProgramData\Mozilla but nothing there either.

Thank you.

I had knee replacement surgery on 10/10/2025 and was unable to access my PC to download email. When I was able to access my PC(physically unable to get to the PC until12/7/2025) email had stopped downloading after 10/27.2025 and many of the ones downloaded were multiple copies of the same text. I decided to just highlight a large group of email and just trash them unread. I have now trashed 5000+ emails and the system will stil not display any after 10.27/2025. I am at my whits end, I am a 78 year old retired non-software engineer and really need some help. This is my primary email account and really need to read what's current.

For 3 days, I haven't been able to access my GMX email account. It tells me every time "Login to the server imap.gmx.com with username '[edited from public] @gmx.com' failed. I hadn't changed anything beforehand and all the entered data is correct. My other accounts like gmail, yahoo, works just fine. Tried installing older versions and still no success. Outlook app works fine either. I'm pretty sure that GMX mail server made some changes that Thunderbird is missing. Please verify.

Best regards

Nilson Xavier

I've been using Thunderbird for years (Windows 11 PC), and all has been working fine as recently as last night. Starting this morning, I continuously get the error message, "Login to server mail.comcast.net with user name xxx failed" (xxx not my actual account name). I've tried the "Retry" and "Enter New Password" options to no avail. I can go directly to the Comcast website, login and get my email that way, but I can't get Thunderbird to login.

To my knowledge, nothing changed between last night and today, but yet something seems to have happened. Any ideas appreciated!

I'm helping someone with their Thunderbird. She says her address book is dropping street addresses. We went through and found a number of contacts that she had updated but they now seem to be be simply name and e-mail address. The only thing I found was the majority of addresses are in the "Collected" group if that matters.

Any hints or tips on this?

I gave up on Outlook after a zillion years using it. When I reset my O/S (win11) I had to reinstall Outlook from Office, all paid up and legal. Nothing but problems trying to get my backed up PST file from previous Outlook. System kept trying to get me to subscribe to Windows 365 crap. I had standalone 2024 version of office. When I installed Thunderbird (I have it on laptops and other computers), I entered my email and voila, in about 1 minute I was sending and receiving emails. I had spent 6 hours on Outlook, even using AI (Copilot) to help me. I was SO IMPRESSED, that for once I donated to Thunderbird, $30 CAD.

Now, I used Mailstore to get my pst file, something I could NOT GET OUTLOOK to do, and have it available to export to Thunderbird, or for TBird to IMPORT from the pst. Neither one worked, telling me that TBird didn't have a profile for the transfer, or some such notation.

Any help would be appreciated. Like many of you, my whole communication life is in those emails (I have about 40 folders where I saved stuff).

I have a problem with Thunderbird on Kubuntu 24.04.3. The drag and drop of mails from inbox to TB-folders stop working after a while. It always happens when I minimize Thunderbird and maximize again, then the drag and drop has stopped working. I have also seen it if I for instance make a new folder, then it also stops working. It has been going on for a while now, at least the last 3 month. I have automatic update on, so I an running the latest version right now 140.4.0esr (64-bit).

Hello,

I have a MacBook Air M2, and I'm experiencing energy usage issues related to Thunderbird. This has kept happening for a long time now actually, surviving through at least two Mac OS updates, and a huge number of TB updates. Everything's up to date. I tried to follow this: https://support.mozilla.org/en-US/questions/1269944 and this: https://wiki.mozilla.org/Thunderbird:Testing:Memory_Usage_Problems?_gl=1*86dj4d*_ga*MTkzNzQ0MjA3MS4xNzYyOTY4OTMx*_ga_2VC139B3XV*czE3NjMzMTM3NDckbzIkZzAkdDE3NjMzMTM3NDckajYwJGwwJGgw but didn't succeed. Actually, in my case, the issue is more noticeable: I normally have TB open in background - sometimes everything's fine, and the battery goes down as normal, while sometimes instead the battery drops quickly, and checking in the Mac activity monitor I can see that the CPU usage of TB is totally abnormal. When this happens, I can actually see the activity bar in TB being live (bottom right corner, as it happens when TB is checking for new mails), but never disappearing. When I notice it, I just reboot TB, and the bar shuts off as normal after a quick mail check. Moreover, checking the 24hr energy usage by app, TB is often on top with nonsense values.

I tried multiple times to rebuild the database, and do most of the tricks suggested, but didn't fix. Yes I have a huge mail archive, but the problem is not the standard management of this database: basically it seems that every now and then, TB decides to run some activity which it gets stuck in, and this kills the CPU.

Thank you in advance for your help!