I am not sure what you mean by "Archive". Thunderbird has its own internal Archive function, which is really just a way of keeping old messages out of sight but readily to hand, and splitting your email store across a larger number of smaller files, avoiding the problems that can occur when working with very large files. As such, these Archive folders are searchable and not committed to any particular account.

So I don't understand why you anticipate any difficulty in working with such an "archive". Maybe when you said "new acount" you meant "new profile". But creating a new profile wouldn't have been necessary.

Or perhaps by "archive" you simply mean old messages, and what would concern me here is that if you have had to create a new account, that is presumably because an old account might stop working, and in this case, I'd want to make a local copy of those older messages while I still had access to them. The Local Folders account in Thunderbird is ideal for this. But you could also move all the messages from the old account to the new if you simply want to keep them all together.

Could someone please answer this question?

Hi Zenos, just saw your answer, thank you. I had to create a new email account because my old one would no longer work with Verizon's new email policy. If you view the attached image,you'll see that TK email is my original email account, and XXX@pobox.com is the new email account. But in creating a new account I see that my archive of emails is under the older account, which I no longer plan to use. How would I move that archive to the new XXX@pobox.com account?

thanks!

They are just folders. Most users seem to be successful just moving folders by drag and drop from one account to another. If all the accounts are POP-based then this should be OK as it's just a local file system operation.

I'm not keen on doing it this way myself if IMAP is concerned because it involves the server. There can be an awful lot of material in a folder and asking email to shift huge quantities of data in one shot isn't well suited to how email works.

I'd manually create corresponding folders in the new account, and move messages by multi-select, right-click and Move to... limiting it to a few hundred messages at a time.

A halfway house might be to move the Archive to Local Folders. This would make a copy that is local and on your own HDD. Whether or not this would be useful to you depends on if you need to have access to these older messages in your new account from other computers or devices, in which case IMAP is a must. You would then want the Archive inside the new IMAP -connected account.

So I'm using a forwarding service, pobox.com, to keep my email the same regardless of which ISP I use. For me to use the smtp.pobox.com server, I had to generate an app password for Thunderbird at the pobox.com website, then use it when TB prompts me for the password. It seems to work fine for a few days,, but then TB gives me the same prompt and won't respond to the password it has been using. Can you help me? thanks