Thunderbird Community Forum

When I try to start Thunderbird on my Windows 11 laptop it does not start properly It is haging ond after a whike i get a message that thunderbird does not respond ("svarar inte" in swedish). Sometimes if I try to reinstall Thunderbird it starts up, But today nothing happens.

I have been using Thunderbird for years with no problems. However recently, Thunderbird very often simply stops responding. Sometimes it just hangs up and sometimes the program bar at the top displays "Mozilla Thunderbird (Not Responding)". If I try to wait for it to respond, it literally hangs for several minutes before it begins to respond again, and often, it simply never starts responding again. It has simply gotten to the point where Thunderbird is practically unusable. All my other application software continues to work with no problems. It's just Thumderbird.

The version number in this submission may not be correct. I can't provide the real version number because of the hangups.

Any suggestions?

Was on version 115, had this problem. Updated to version 155, same problem. One of the email accounts I set up on Thunderbird is redacted1@lake48.net, registered with 123-Reg. However, this is a forwarding address and has no email server, which is why I am getting the error now.

Messages addressed to redacted1@lake48.net are forwarded to redacted2@lake48.net, which does have a server, My system was to download from there and use a rule to divert the incoming message to my redacted1@lake48.net Inbox. This has worked OK until now. Thunderbird gives me this error right at the start and then does not respond, so I cannot get in to investigate account settings, and cannot access emails in other accounts such as gmail. 123-Reg has today changed its system, assuring me I don't need to change anything. Clearly I do, but I can't get in to change it.

What should I do to resolve this? I have no other access to my emails.

Since 3rd September 2026 Thunderbird opens a system integration window and then goes to not responding. I cannot access my emails through this software at all at the moment as there's no way past his pop up. Version 153.1.1, Windows 11 Home.

Been to various sites for diag info. I have uninstalled antivirus and tried it, no joy. I have done all the following to each folder - compess, repair, deleted old emails, etc. (I actually have rules that are to do this automatically). I have captured config info, uninstalled and installed fresh. Still have the problem. -- and finally restored so I still have email addresses, etc. etc. This problem has started for me with in the past 2 weeks.

1) ALSO note: I am running W11 home. Mozilla keeps calling this W10. I do not know what the difference is between Home and Pro, but I am planning to upgrade to PRO within 2 months (looking for a reasonable deal on the cost of the upgrade). 2) Wife's computer is W11 Pro, she does not have the problem.

I'm running TB on Windows 11 on a Dell Desktop machine. It's a pretty basic installation with EE Cyber security, which is I think Norton. I've been using TB for a couple of years but recently it has almost stopped working. I notice from Task Manager that TB is massively leaking memory and consuming much CPU time. I don't think I have any add-ons and I only use TB for email. It's now so bad that I'm even unable to go into TB's Settings or Tools or anything else. I've tried creating an exclusion for TB profiles and TB.exe in the Norton. I've tried starting TB in troubleshoot mode but all to no avail. I have it in IMAP, Port 993, SSL/TLS for incoming mail and Port 465, SSL/TLS, Authentication Required for Outgoing mail. I'm currently often unable to even access mail previously downloaded to the local Mail folders, TB is just hanging with the bar in the lower right corner endlessly running along. Most puzzling of all, is that very occasionally is starts working again and then I dare not switch the machine off! It's become an indeterminate system. Please help, I'm nearly eighty and trying to organize my holiday, which is needs email to make bookings. Thanks in anticipation.

I'm experiencing an issue with Thunderbird when trying to open attached PDF files. As soon as I double-click a PDF attachment, Thunderbird immediately shuts down completely. When I reopen Thunderbird and try again, the same thing happens.

I have already restarted my computer, but the issue persists. The only way I was able to open the PDF files was by accessing the email directly through Outlook.

Still having issues with Thunderbird on my Windows 11 laptop. I tried reinstalling the program but still locks up. Any suggestions or comments would be appreciated Thanks Dave

I was using TB like normally on windows 11 when it crashed. Now every time i try to open the app it prompts me to send in a crash report, but every time i press "restart thunderbird" a new window with crash report shows up. I have tried writing a comment, checking and unchecking all the boxes and pressing quit thunderbird. But i still get sent into the loop.

Thunderbird is very glitchy and slow after the latest update - Thunderbird 140.11.1esr (20260522210329)

Especially, when I get a new email, Thunderbird stops responding for 5-10 seconds and then starts working.

I am using Windows 11

roland.multhaupt

18. Juni 2026, 07:13 GMT-6

Firebird is so slow now, that I can rarely receive the code that you send me. Have to take annother programm for that. Freezes even when trying to mark a mail or erasing it. WIN 11. The programm is working well at my wifes laptop also WIN 11. 2 month ago it worked fast and fine. Working in Troubleshooting mode does not show any spam ordner like before and it does not run better. I also downloaded the last version. No change! I would like to uninstall the programm but did not dare due to perhaps loose all my mails. Could you help me please? Thank you!

Suddenly Thunderbird takes a long time to download even a few (10-20) emails from Gmail and then it freezes on an email and as I click on different emails only the original one shows on the bottom half of the screen, even if I change to a different folder/email account. Also it will not close when I hit the X in the upper right corner.

If I click on one of the other apps, such as Calendar it goes to calendar but when I go back to email it still shows that same frozen email.

I tried clicking on the three bars (hamburger) to find the Thunderbird version and nothing happens.

I have restarted the computer but that has not helped.

This is an add on to the previous portion that I wrote yesterday. Today nothing shows in the portion where I usually view the message after I've clicked on it. Also the options in the tool bar such as File, Edit, View etc. do not respond to a click after the first time I have attempted to look at a message.

I am considering uninstalling and reinstalling. If I do that will it find all my emails and folders etc. again? There are a few emails that I am quite desperate to access that I have put in folders.

I'd really appreciate any help I can get on this as some important work is being delayed until I can access those emails.

Thanks for any assistance!