You cannot change an existing account. See http://kb.mozillazine.org/Convert_a_POP_account_to_a_IMAP_account

Thanks, Christ1! It's useful to know I can't convert the POP to IMAP. I was successful, at the gmail website, in copying emails from the All Mail folder to my Inbox, but then I couldn't download them via Thunderbird (as I'd been previously able to do with my other two IMAP email accounts). Any suggestions on how THAT might be accomplished? Again, thanks for getting back to me!!

It's useful to know I can't convert the POP to IMAP.

Please read the article linked above.

I was successful, at the gmail website, in copying emails from the All Mail folder to my Inbox

I don't think I can follow what you did and in which account.

Hello again, christ1! Thanks for your continuing interest; MUCH appreciated on this end. You can ignore all the verbiage about my copying a file and folder in my failed (and, impossible, as you point out) attempt to convert the first of my three e-ddresses from POP to IMAP. I'm through trying that.

Here's the problem, which followed a disk crash: in my Tbird inbox for the IMAP account, there's a two-month gap, namely the emails that arrived at the gmail server since I last backed up My PC's Tbird's .default directory. My thought was that if I went to gmail's website and copied the desired emails from my All Mail folder to my Inbox, then I hoped Tbird would download them. This did, in fact, work for my 2nd & 3rd e-ddresses (which are both IMAP), so you can see why I first tried to change the 1st e-ddress from POP to IMAP.

For that 1st e-ddress, then, I WAS successful in copying the almost 300 relevant emails from the All Mail folder to my Inbox (at the gmail website), but Tbird doesn't download them to my PC, and I have no clue why.

Is that any clearer? Again, thanks for your continuing interest in this subtle problem!

Dave

Sorry; the first sentence in the 3rd paragraph should have said "in my Tbird inbox for the first e-ddress (which IS a POP account), there's....."

my failed (and, impossible, as you point out) attempt to convert the first of my three e-ddresses from POP to IMAP.

That's not what I said. Again, please read the article. Creating an IMAP account would still be the solution to your problem.

The first sentence in the link you sent says, "Thunderbird doesn't support converting a POP account to a IMAP account. Its possible to hack the files in the profile to convert the account, but its tricky and time consuming and requires knowledge most users don't have. Its much quicker and safer to create a new account and move the messages to it, and then delete the old account." Then it goes on to detail how to move emails, create a new IMAP account, and delete the old POP account. My thought was that I would be prevented from making a new IMAP account with the same e-ddress as an existing POP account. Do you know if that is the case? If it's NOT, I'll certainly try that... Again, many thanks! Dave

It's not. Just follow the instructions.

Wow! I certainly hope you're right! I'll give it a whirl, and report back! Thanks!!!!!!!!!!!!!

You, sir or madam, are a GENIUS!!!!! It worked! All the emails I'd moved on the gmail website (from All Mail to Inbox) are now downloaded to my Tbird inbox for that new IMAP account! You're the greatest!

You wouldn't happen to know how to change the order in which the accounts appear in the leftmost Tbird pane, would you? The new account I added is now at the bottom. No biggie, but I thought I'd just ask. I didn't see any way to do it either by R-clking the folder in that pane, or by trying it in Tools/Accounts

You wouldn't happen to know how to change the order in which the accounts appear in the leftmost Tbird pane, would you?

Install this add-on. https://addons.mozilla.org/en-US/thunderbird/addon/manually-sort-folders/

Thanks AGAIN! Is there anything about Tbird you DON'T know?!!! I owe ya, bigtime! Dave