First, all accounts need to be IMAP, Here are the steps:

here is the info in brief steps:

BACKUP Use these steps to create a backup of your profile

1. ensure thunderbird is not running
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

RESTORE Use these steps on the other PCs

1. ensure thunderbird is installed and NOT running
2. enter %appdata% in search window on task bar and press Enter key
3. 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
4. start thunderbird and all should be there

David,

Thank you very much for the prompt and detailed reply. That should solve my problem.

Alan

You are most welcome. :)

David, I finally got around to installing the second instance of Thunderbird on a different computer and everything went well. A couple of questions about operation, if you will:

• First, can both instances of Thunderbird be running on the different computers at the same time?
• And second, will both copies synchronize? That is, if I delete an email on one computer, will Thunderbird on the second computer automatically delete it as well? And will both instances receive the same new email(s)?

Thanks, Alan

Yes, to both. If the account is IMAP, all messages are on the server, so deleting it from one PC causes the status to be updated on both