Changing Thunderbird from IMAP to POP3

I suggest you read the support article on the differences between IMAP and POP mail. See https://support.mozilla.org/en-US/kb/difference-between-imap-and-pop3

I have no idea why you made the change, but from what is posted here I do wonder if your choice of protocol actually meets your needs.

One of the primary differences between IMAP and POP is that POP only sees what is technically called a maildrop which most providers have interpreted to be the inbox, where incoming mail is "dropped" awaiting collection. It actually has no concept of folders so it will never bring mail that is stored somewhere other than the "maildrop" to the local machine.

Your only real choice here is to move mail to the inbox so it will download or use IMAP if synchronization of folders is important for you.

See RFC 1939 for full details of POP3 protocol. https://www.rfc-editor.org/rfc/inline-errata/rfc1939.html

Matt, Thank you for your response! To answer you question/comment from your help suggestion, I'm using Centurylink for my ISP. They are the only provider I currently have for E-mail. The IMAP was working when I initially signed up with them. About 2 years later they did a major upgrade to their system. From that time forward, things began to change for the worse. I battled with the S-L-O-W downloads. (Which got S--L--O--W--E--R and S---L---O---W---E---R!) This is why I have switched back to a POP3 Protocol and why I'm needing help to re-gain all my e-mail folders.

NO, I didn't want to do this, but after I tried all the different remedies I could think of, this one was the only way I got back to a usable E-Mail Client. Hated it, but something had to change. Centurylink had no remedy. They only blamed the issue with my PC, Router, Connection(s) etc..

When Microsoft changed their TPM for Windows 11 which trashed my current PC for any further updates, I was forced to purchase a newer PC and Laptop to accommodate the updates with Windows 11.

We will be getting Fiber here soon and I'm waiting for it to be completed. I'm also waiting for Thundermail and Thunderbird Pro to become available. As soon as those are released, I'll be eagerly looking into them for all my e-mail.

jmil43, I would think that you could have an IMAP account and a POP account in Thunderbird simultaneously and use the the ImportExportToolsNG add-on to export messages from the IMAP account and import them into your local folders account. Messages would stay in the same folder structure. You would not have to move them all into the POP inbox and file them later (if you file). When you are done copying them, you could make a back-up, delete the folders and messages off the server, and delete the IMAP account in Thunderbird.

Matt, is there a reason why that would not work?

(My response to the bad service from Centurylink would have been to switch to another e-mail service provider immediately instead of switching to a POP account.)