Sometimes the problem is that thunderbird was running when profile was copied. In that case, the profile is corrupted and thunderbird starts fresh. OR, there may have been an error in the process. Here are the basic steps:

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

If thunderbirs still prompts to create an email acccount, skip it and click help>troubleshootionginformation' - then, scroll down to 'profiles' in left column and click 'about:profiles' - you should see yours here. click the 'open' button

Solved, or at least worked around. I simply deleted everything out of the new profile folder and copied everything from the original into the new. There appear to be few minor preferences (sort order, threading, etc.) which have not been picked up but the emails etc. all seem to be there.