Back where, in Yahoo Mail? That's not feasible with that many emails.
By default, a POP email client like Windows Mail deletes mail from the
server after a successful download. You can change that default if
you wish, but it would only affect newly downloaded messages.
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments. After that, you can post your question and our members will help you out.