I haven't seen this situation mentioned in the forum yet, so I started a new thread.

I've been asked to copy email from one mailbox to a folder in another mailbox. My first idea was to just open both mailboxes in a mailclient, but that would move the mail (not copy it), and I'd really rather not have to open the mailbox if i can help it.

I don't know if imapsync is the answer, but I tried it once a while back and it sucked up all the resources and crashed the mail server (not a good day). That makes me hesitant to see if this is even the correct tool here.

What's the best way to get the mail from one mailbox into a folder of another mailbox (without removing mail from the first mailbox)?