Please provide more information on the problem. What information do you need?

David, thank you. On my old computer of 15 years , running windows 10. I had Mozilla Thunderbird as my main email....greg@chalaine.com. The way I would start Thunderbird, I would click the start button. The side bar pop up and the icon was close to the top usually. I never put the shortcut on my desktop. Not that matters, just giving details. As the computer was starting to show startup and storage problems, I decided to take it to my person that works on and sells computers. He sold me a new one with windows 11. I found the Thunderbird folder under program files on the old hard drive he placed in the computer for me. I have tried opening Thunderbird, but was asking for a password. I was never ask for a password on the previous computer. I tried a few that I thought, but no go. I set up a primary password. Still no go. I have gone as far as I can go on the configuration, but get stopped at password. I don't see where I can say forgot password. Any ideas?

All that info was/is on old computer. The program was probably in program files and the profile was in the c:\users\<yourid>\appdata\roaming]thunderbird folder. Copying the profile may not have been done. Also, check to see where thunderbird is installed. is it in c:\program files\Mozilla\thunderbird (or similar), or elsewhere? I ask because there is also a Microsoft version that installs to different location.

I have searched for the appdata/roaming/Thunderbird with no luck. The Thunderbird golf is in the program files folder.

If you can log into thunderbird, please do this: - click help>troubleshootinginformation - scroll down to 'profile folder' and click 'open folder' - do a screenshot of the profile there. that will be helpful

Do you still have the old computer? That may prove priceless.