You cannot have done what you said, because an account in Thunderbird cannot be changed from POP to IMAP or vice versa. You must have set up an entirely different account using different mail servers. I'd love to know what makes you think you would be able to access the mail stored on the old mail server using the setup for the new mail server…

The old account should still be present in Thunderbird if you didn't remove it, but the old email provider may not allow you to access it anymore after having switched to another email provider even if you try to do so using the old account settings…

Depending on what you did (which cannot be what you say you did), though, the mail stored locally on your computer by Thunderbird may still be lurking around somewhere within your profile folder and you may be able to get it back.

The following article explains what's a profile and how to locate the profile folder in the filesystem: https://support.mozilla.org/kb/profiles-where-thunderbird-stores-user-data

For each account in Thunderbird, there is an account folder named after the incoming mail server in the profile folder, either within Mail if the account is POP, or within ImapMail if the account is IMAP. Check whether you may find a folder for what would have been your old email account, to get an idea of whether your mail may still be there, and post back with the results.

Thanks for your response David.

I did what I said. The bad part was that I changed to a different host, as I mentioned, and assumed the old emails would remain locally on my computer. My web hosting account expires tomorrow and I went with just an email hosting service until my domain expires. (I no longer need web hosting.) I guess I can go back to my web host's settings temporarily until I can somehow back them up to my pc. Will that work?

Thanks for your time, ginger

I did what I said.

No, you didn't, because what you said is IMPOSSIBLE. Either you (1) changed mail servers, but the type of account (POP/IMAP) remained the same, or (2) you did set up a new account in Thunderbird, which is the ONLY way you can change from POP to IMAP or vice versa…

assumed the old emails would remain locally on my computer

And they would if the old account was POP as you said, but everything you're saying would seem to indicate the old account was IMAP as well, not POP, in which case yeah, all your mail stored locally on the computer for that account would be gone after Thunderbird synchronised with the new server…

I guess I can go back to my web host's settings temporarily until I can somehow back them up to my pc. Will that work?

If the account does still exist on the old host and you're allowed to access it, yes. You could then create folders under Local Folders, at the bottom of the list of accounts in the folder pane in Thunderbird, to store and organise your mail locally on your computer there however you wish, independently of any mail account you may have.

Thanks for hanging with me. :)

So, if I change my settings back to my webhost temporarily my inbox wil repopulate with the emails on that server? (Remember, that web hosting account is closed tomorrow.) Then do I just create a folder (under Local Folders) for each email account and drag and drop from each account's inbox, sent etc. into the folder created for each? These are stored on my pc then aren't affected when I go back and change the server settings to the email host that I signed up with which will connect to that server and redownload the few messages that I have from that host in the last couple of days?

Thanks again for your help. It is much appreciated!

ginger

Right. Mail stored in Local Folders becomes detached from the account you moved/copied it from, and hence not affected by anything you may do to the account.

I would recommend you to set up a new mail account for the new server, though, even if the account type is the same, because the account is not the same, then remove the old account from Thunderbird when you no longer want it there.

Everything sounded good until "set up a new account for the new server". Do you mean a new email address? I'm only allowed one email account on this new email host. The rest of my email accounts are with att, but I wanted to keep one with my domain name until that expires. I'm not sure the new email host will allow me to change the email address that's associated with the account.

Thanks again, ginger

No. I mean set up a new email account in Thunderbird for your existing mail account on the new server, instead of reusing the existing setup in Thunderbird like you did. Even if the email address is the same, you're still managing two email accounts, the account on the old server and the account on the new server, and hence it would be better if you set up each of those accounts in Thunderbird, because they are different accounts (hosted on different servers) even if the email address is the same for both.

I hate to be clueless, but if they're both the same email address how will Thunderbird differentiate between them. Do I give them a different Account Name in Settings? I've always just used the email address for the Account Name.

ginger

Again, because the mail servers are different… You may give each account a different Account Settings > Account Name. It defaults to the email address, but you may type there whatever you want to help you, not Thunderbird, differentiate them…

Thank you, thank you, thank you!