Are you under some misapprehension you are telling anyone other than your fellow users you are not happy? You posting reads like you are, but this is a peer forum. There is a feedback link in Thunderbird on the help menu that links here connect.mozilla.org where you can offer feedback that may get to the paid developers.

There are also a collection of mailing lists operated bu the project where you might be able to air your views on your user experience. For example the UX list (User Experience). https://thunderbird.topicbox.com/latest

I do not see any specific issues with windows 11 however, transition issues tend to be operating system agnostic.

Perhaps you didn't read my posting with an open mind (or didn't make it past the subject heading). I'm complimentary of the work you and like-minded folks do to help those of us who need the input.

Windows 11 is a disaster for those migrating from Windows 10. Shall I list all of the issues I've encountered and all of my older software that is no longer valid? $$$

Free upgrade to Windows 11 (which I never used) was obviously a scam to get people to enroll their old "Microcrash" software to a subscription basis. Every Microsoft Office program I was using now requires a subscription, even though I paid the big bucks to get the originals. Those who support the latest trend by Microsoft to deactivate our original software should be placed in the "minority opinions" folder.

Al Smith, age 72, retired airline pilot, computer programmer and freelance advocate for the minority opinions

By the way, I finally was able to create a new profile for Thunderbird and transfer my old profile from Windows 10 to Windows 11. It was not easy nor intuitive. Especially, NOT intuitive.

A couple of hints to you: Using POP3 was imperative. Using IMAP failed every time.

Even with new installations of Thunderbird on Windows 11, regardless of the IMAP vs. POP3, no profile (of any type visible in Windows Explorer (with hidden files visible) could be seen. Thunderhead must be defective.

I truly do want to provide constructive criticism.

Al Smith

Did you install TB from the MS Store? It keeps the profile in a location that is different than the one downloaded from thunderbird.net.

https://support.mozilla.org/en-US/questions/1434631

I concur with sfhowes. We regularly post the transfer information and it has been a rock solid transfer process.

Here is the link for moving a profile in Windows when installed in default location:

https://support.mozilla.org/en-US/kb/moving-thunderbird-data-to-a-new-computer

here is the info in brief steps:

1. ensure thunderbird is NOT running on old machine
2. enter %appdata% in search window on task bar and press Enter key
3. this should open windows file explorer in Appdata\roaming folder
4. highlight the Thunderbird folder and copy to external media
5. ensure thunderbird is installed on second computer and NOT running
6. enter %appdata% in search window on task bar and press Enter key
7. you should be in Appdata\roaming folder , copy&paste the exported Thunderbird folder there. This may prompt to overwrite an existing folder of same name. allow it
8. start thunderbird and all should be there

And a search on this forum for 'transfer' would have brought up repeated posts on these steps. Your intent on being constructive reflects a lack of research on the information available here.