Hi. Over the years I have let my AOL account grow to an enormous size. About 80,000 emails. Unfortunately AOL web interface is useless, and always has errors, very limited search and filtering etc. so I decided to give Thunderbird a shot to help me get my 80000 down to a reasonable amount and then go on an unsubscribe kick and create rules . Anyway, I do want to keep a backup of many of my emails in local folders. I have already started doing this and I referred to this an old thread from 2015 that unfortunately is closed so I cant reply there. I have two questions about by Toad-Hall. <blockquote>Synchronise your subscribed folders to get a copy in thunderbird. <br> Then go into offline mode.<br> Highlight emails you want to move<br> ...<br> right click on highlighted emails and select 'Copy to' choose a folder in Local Folders account.<br> Check you can access those emails via Local Folders.<br> If you have got a copy into Local Folders, you can then choose to delete the emails that are in the imap folder.<br> then go back to 'online' mode.<br> imap folders will synch with server to update the server. </blockquote> <br> Why is it necessary to copy vs move? Is it so that the actual process of "delete" after is more likely to trigger a delete on the server than a move? Also, why is it necessary to go in offline mode to do this procedure? Thanks.