After years of using Thunderbird and POP, I am looking to move my mail back to the server and use IMAP to make sync'ing multiple devices easier.
The aspects of creating the IMAP user in Thunderbird, then dragging the existing files over makes sense. BUT before I start I am wondering about the fact that these folders have messages from multiple email accounts.
We have multiple email accounts for the business, and over the years have stored message based on category rather than email address, so most every folder has email from multiple accounts.
If I drag a file to the new IMAP account with mixed addresses, will it upload the whole folder or will it choke when it reaches an email form another account?