Toad-Hall, I can live with the 'accessibility.force_disabled' setting at 1. I use no add-ons, no calendar, no chat, just IMAP email. All I need is to send and receive HTML-friendly email. Maybe we need "Thunderbird Light" with no frills.

Again, many thanks for your patience and for uncovering the bug also reported by another. At least I know it's not something I am doing wrong.

I have the exact same problem. Thunderbird stops responding while composing a message in HTML. It started a couple of months ago when Thunderbird recommended that I change to the release update channel and a newer version was installed. I don't remember the older number nor the newer version number at that time. I was running Win10 Home at the time. I had been running Thunderbird for a few hears without a problem under Win10.

I have not found this Not Responding While Composing problem mentioned in a wider web search, only in this one report in this particular forum.

I have since updated my Dell XPS 8940 to Win11 Home. The Thunderbird problem continues under the new operating system.

As of today, I am using Thunderbird 141.0 (64-bit) on the release update channel. The problem has continued through a few Thunderbird updates and the update from Win10 to Win11.

As the OP describes, Thunderbird frequently stops responding when composing a message. I am able to click on X in the upper right corner of the main window to close Thunderbird. I save after every few words so after restarting Thunderbird I can continue composing from the saved drafft.

I have tried turning off hardware acceleration and running in Safe mode, but the problem persisted.

Perhaps I will have to remove Thunderbird completely from my computer and start over with a clean install. But I have a few years of data stored on my computer so I've been reluctant to do this as I don't know that this drastic measure would help.

Dell XPS 8940, Win 11 Home 24H2, NVIDIA GeForce RTX3060 (Studio driver 32.0.15.7700 updated 7/14/2025), 64 GB ram

Granddaddy, start with Toad-Hall's message on June 7, 2025. That disables some some Thunderbird features that I never use anyway (for me it is an email program, nothing more) but it does kill the bug.

Granddaddy, start with Toad-Hall's message on June 7, 2025. That disables some some Thunderbird features that I never use anyway (for me it is an email program, nothing more) but it does kill the bug.

Link to that comment: https://support.mozilla.org/en-US/questions/1514833#answer-1740015.

Hi Dan Landiss Can you please mark my comment as the Chosen Solution, so that people with same issue can find a current solution more easilly. Many Thanks. https://support.mozilla.org/en-US/questions/1514833#answer-1740015

Using T-Bird 144.0.1 (64-bit) on WIn 11,

I tried setting 'accessibility.force_disabled' to 1 and that seemed to work, but ended up hanging after composing and sending a couple of mails.

My Send is now set to Both HTML and Plain Text (from the previous Auto) -still no diff.

Did a win update to 24H2, —still freezing as I hit send.

I did notice that it hangs just after I hit the Send button, (which did turn grey as I hit it). I also noticed that it got as far as highlighting the first spell checking word and then hung immediately. This happened reliably on a few draft emails I tried to send. I disabled spell check and have been able to send email without hangs.

Hopefully this is helpful info for the Bug Report —and for all you good people giving up your time to help others.

Using T-Bird 144.0.1 (64-bit) on WIn 11, I tried setting 'accessibility.force_disabled' to 1 and that seemed to work, but ended up hanging after composing and sending a couple of mails. My Send is now set to Both HTML and Plain Text (from the previous Auto) -still no diff. Did a win update to 24H2, —still freezing as I hit send. I did notice that it hangs just after I hit the Send button, (which did turn grey as I hit it). I also noticed that it got as far as highlighting the first spell checking word and then hung immediately. This happened reliably on a few draft emails I tried to send. I disabled spell check and have been able to send email without hangs. Hopefully this is helpful info for the Bug Report —and for all you good people giving up your time to help others.

Thanks for the report. Changing that setting has been known to work only when composing, so I think you have another issue - hang on spell check, maybe? Try re-enabling spell check and see what happens in Troubleshoot Mode.

It may also be 'hanging/freezing' because you have an Anti-virus scanning all outgoing mail OR scanning any file that opened. Basically, the Anti-virus is temporarilly taking control. When you hit send, the sent file is opened in order to write to the file and the frafts file may also get opened in order to remove the saved draft.

The only proper method to test whether something eg: Anti-Virus is causing the issue is to do this:

1. Exit all programs.
2. Connect laptop/computer to the router/hub using an ethernet cable.
3. Restart computer in 'Safe Mode with Networking'
4. Start Thunderbird
5. Perform a send email.

If all sends ok then set up the no scan exclusion for the Thunderbird profile folder. However, it is advised that you access the Anti-Virus and set up an exception to not scan anything in the Thunderbird profile. If you have Windows OS and downloaded/installed Thunderbird from the official website : https://www.thunderbird.net/en-US/thunderbird/all/

Then this is the 'Thunderbird' folder you need to set up as an exception: C://Users/username/Appdata/Roaming/Thunderbird

For those who found the accessibility preference change helped...

If you can supply the information mentioned at https://bugzilla.mozilla.org/show_bug.cgi?id=1972457#c27 it may be helpful.

Thanks.