yes, you can do that. if it is IMAP, click file>offline>download to ensure you retrieve headers and content. once done, install importexporttools addon, highlight sent folder, rightclick and select option to export mbox. then, on new pc, highlight Local Folders, rightclick, select importexportoption to import mbox. then, you will have the Sent folder in local folders. if you want to upload, I suggest creating a manual filter and do slowly. IMAP was not designed for large volume uploads, so it can get a bit dicey.

What would you consider a big download? At this point, I really wouldn't need more than the current year's sent items, so I could delete everything older before exporting.

Anyway, thanks for the tip. I've installed the add-on on the new computer, but not yet the old. If I hit a snag, I'll follow up.

If you have set up an IMAP account on new computer then the Sent items should auto appear.

So now I'm wondering if you had a Pop account on old computer.

If you had a pop account etc and a load of pop account folders etc on old computer then you could have moved the entire lot onto new computer and never needed to create any mail accounts. Basically use whatever was set up previously. If you feel this is something you want to do. Overwrite everything and use all the old profile etc which includes address book, calendar, preferences etc then let us know and we can provide additional information.

But if you have decided to do things differently and swap from a Pop to now use an Imap you need to be aware IMAP works very differently from POP.

In Pop all emails in all folders are stored on your computer. There is no synchronising of any folder. Pop is a completely independent copy on your computer. You can choose to leave a copy of messages on the server or not.

Imap accounts can only display whatever is on the server. All imap folders synchronise with server folders. If you delete anything from webmail account it will get deleted from imap account and vis versa. You have the ability to choose whether to download full copies or only headers and this can be done on a per folder basis. You can also choose to limit x amount of emails in any folder which are kept as fully downloaded emails. You can download full copies in all folders and then perform a backup so you can keep a copy comletely independent of the server. But, you cannot truely regard any imap folder as an independent copy from the server.

You can import mbox files from old profile, but they need to be imported into 'Local Folders' mail account. If you then want to get some back onto the server - you highlight small batches of imported sent emails, right click on highlighted emails and select 'Copy-to' and choose the imap account default 'Sent' folder. REpeat gradually. Please be aware this can take time and servers do have limits on what can be uploaded to server via imap and these limits are very different from the usual send limits.