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Hi everyone,

I’ve run into a weird issue with Thunderbird on macOS 26 (Tahoe) and I’m wondering if anyone else has seen this.

When I close the main Thunderbird window using Command + W or RedDot Close Button, the window disappears like normal, but something is still left behind. It’s like an invisible or “ghost” window stays on the screen. Because of that, I can’t click anything that was underneath the Thunderbird window. The area is still blocked as if the window never fully closed.

If I open Mission Control (F3), I can see an empty tile where the window should be, which confirms that something is still there even though it’s not visible.

A few details: • The problem happens every time I close the main window with Command + W • Thunderbird keeps running in the background, but I can’t bring the window back unless I quit the app completely • This only happens with Thunderbird, no other app on macOS 26 has this issue on my machines • On previous macOS versions I never had this problem

System info: • macOS 26 (Tahoe), fully updated • Latest stable Thunderbird release • Mac mini M4 and MacBook Air M4

It looks like some kind of window management bug on macOS 26, but only triggered by Thunderbird.

Has anyone else experienced this or knows if it’s a known issue? Thanks!

On the 20, of October I was forced to re install Windows 10. Kept my data but I had to re install all my apps. With Thunderbird I follow the same procedure I used with Firefox: After installation I copied the profile folder from my backup and replaced the new one. That worked out well. With Thunderbird, I followed the same procedure, all my emails where there but not my local folders. I am attaching several snapshots to illustrate my steps. Image 1 "local folders now" Image 2 "Profile Folder". (why there are 2 sub-folders)? Image 3 "Mail in the profile folder" Image 4 " List of folders in my Local Folders" The are there, how do I get them back on Thunderbird in the correct place "Local Folders"? Thank you for your help again. Regards Ilio Pieroni

When I use IMAP/SMTP incoming/outgoing servers, sending message fails: it asks me to enter another password, but does not give me a prompt to enter it. When I click retry it hangs indefinitely. However, if I create an account with Exchange/Office 365 account, sending mail works just fine. This problem occurs very recently, probably due to an automatic update to Thunderbird 140.4.0esr

Any clues and cues would be very welcome

after using thunder-bird for years I suddenly today cannot read or send messages. I keep getting the following message; Sending of the message failed. An error occurred while sending mail: Outgoing server (SMTP) error. The server responded: Try again later, closing connection..

Hi, I’m trying to use the audioTracks API from the Web API. I found out that I need to enable a specific flag in Firefox, but it doesn’t seem to be working as expected. Even though my video has multiple audio tracks, it only shows one audio track and doesn’t list their properties correctly. But In Chrome, Edge and Safari it is working as expected. Here I am attaching the screenshots of both Firefox and Chrome for comparison. The Blank drop down is from FireFox.

I was trying to change the time emails are kept on the server so I went into "Account Settings" and now Thunderbird is locked onto this page. I get a "Mozilla Thunderbird not responding" message when I try and click on anything and I can't get out of this page nor access my Inbox. I've tried starting Thunderbird in Safe Mode which didn't work. I then uninstalled and reinstalled the latest version of Thunderbird but when it starts it goes straight back to the frozen "Account Settings" page. I've checked my profile and there is a new profile that was created with today's date. There is also a profile from June 2025. If the old profile contains all my emails and folders up to yesterday, that would be OK.

I have installed Thunderbird on a new computer and copied my profile from the old computer as per instructions on the Mozilla site. However on the install on the new computer the LOCAL FOLDERS, sub folders which I use as archive storage do not contain the messages as per the my old computer. The sub folders are named correctly.

I have attached photos of the sub folders from the old computer showing data in the sub folder and also the new computer showing no data.

Please advise how to retrieve the data for the new computer.

If a folder has been compacted and now only shows emails that have been starred, is there any way of retrieving the files that have been compacted? I am using Thunderbird version 144 on Windows 11 Thanks Michael

The offline package download speed is too slow and sometimes fails. I hope it can be provided separately, like interface language packs, just as Debian has separate interface language packs.

Hello -

My bookmarks (400+) that I have accumulated over several years were all gone when I signed into my computer recently. I tried to restore them, but I was unable to get them back from all of the 15 backup points. I kept getting an "unable to process backup folder" error message. I only have one Firefox profile that I am currently signed into.

I use CC cleaner to clean my computer weekly and sometimes use the custom clean feature to clean up cookies and browsing history, but by default the clean bookmark backups box is unchecked and I have never had a problem using it before. I suppose it's possible that I may have checked that box, but I don't know if that would have also wiped the bookmarks off my browser. I am also checking with CC tech support to see if they have any answers. Suppose I may be out of luck if so.

I also sometimes go into FF settings and clear browsing history and cookies, but I don't think there's even an option to wipe out all bookmarks. I have also been doing that for years, and have never had an issue before. Does anyone know if there's a way to re-download my bookmarks from the cloud, or do I have to start all over again?

Any tips would be appreciated, thanks.

Hello Support Team,

Since updating to the newest Firefox instance, anytime I try to login to my Hotmail/Outlook account I get the following error: "You've tried to sign in too many times with an incorrect account or password." If I wait several hours I can login with the Firefox browser into my Hotmail/Outlook account successfully. This happens every singe time I try to login to the site after a period of time. Alternatively I can go to any other browser and login immediately with no issues.

Troubleshooting:

• Removed/Reinstalled Antivirus/Firewall Software (Did Not Resolve)
• Removed/Reinstalled Firefox with fresh instance (Did Not Resolve)
• Disabled Extensions (Did Not Resolve)
• Disabled Privacy Settings (Did Not Resolve)
• Cleared Cookies, History, Cache (Did Not Resolve)
• Cleared Forms (Did Not Resolve)
• Tried Private Window (Did Not Resolve)
• Tried Troubleshooting Mode (Did Not Resolve)

I don't want to have to switch to another browser for my browsing needs, but this has become a major issue for me. What else can we do to troubleshoot and resolve this issue?

Thank you in advance for your time.

Cheers, Jason

Confused. Version 144.0.1 | Released October 16, 2025 Says 32 bit. I thought I downloaded 64 bit.

Problem: Freezes when I click anywhere on TBird desktop

How do I address the freezing problem?

Thanks Robert

My inbox was inadvertently moved down in the list of folders and I am not able to drag and drop it back to the top. It looks like there used to be a "Manually sort folders" extension but it no longer works. Is there a way to reorder folders manually? I use 140.0.1esr (64-bit).