I am not sure the steps you took, but I suggest this: - exit TB on old pc - copy c:\users\<yourid>\appdata\roaming\thunderbird to external media - be sure TB is not running on new PC - copy the thunderbird folder from external media to c:\users\<yourid>\appdata\roaming to overlay the current thunderbird folder. If prompted for overwrite, allow it. - start TB and all should be there

Followed instructions, did not work. Got an error saying "Your Thunderbird profile cannot be loaded. It may be missing or inaccessible" . I tried renaming the profiles.ini file to profiles.iniOLD and restarted TB. It prompted me to create a new profile and of course when it loaded, it came in with no mail. HELP please.

If you had copied the thunderbird folder intact from old to new, with no changes, the process works. Somehow, your profiles.ini got changed. That is the one file that thunderbird obeys: if the profile being pointed to doesn't exist, you get that error message. To fix this, you can edit the profiles.ini so that all pointers are to the correct profile. Any spelling error will cause the message to occur.