This happens because Thunderbird must be told where the profile is; it doesn't 'look' for it. Thunderbird opens this file: c:\users\<your id>\appdata\roaming\thunderbird\profiles.ini to get the name and location of the profile. You can edit that yourself with Notepad, or you can, from desktop, do this: - click windows key and 'r' key - enter thunderbird.exe -p and press enter - this is the profile manager. click the 'create profile' button and follow the steps to locate your profile, give a shortcut name, then click 'choose' and then finish and launch

Thank you for your suggestions. I’m afraid as a pensioner I must confess that try as I may to follow your instructions, I have not succeeded. I transferred the profiles from my external hard drive to the C drive but it still only shows a profile folder which is empty. I’ve also gone to help in Firefox and then further help. I see the list of profiles but don’t know what to do next.

ok, please provide in detail what you did and where the profile was copied to. With that, I may be able to give more instructions. screenshots of what you see may be useful. Thank you

I have added the photos to show you what I have on my pc after %APPDATA%\THUNDERBIRD\Profiles\ was I put into search

Those photos showed several profiles. It may be simpler if you just post screenshot of your profile that you copied it, as then I will know which one to focus on. Then, I think some of the folders being shown can be removedd.