That is what IMAP is designed to do. Both/all of your computers look at the same set of folders and messages, so all of them see the same thing. Any change on one is rapidly propagated to all the others. It doesn't help with setting up the accounts, but that generally isn't too painful to do over on each computer. You could copy your profile from one machine to another and that will transfer account settings, address book and your local stores of email messages. https://support.mozilla.org/en-US/kb/profiles-where-thunderbird-stores-user-data I use online address books and calendars so that this data is also shared between computers.