I have over 18,000 e-mails. How do I delete them ALL at the same time?

You can delete them all at once----BUT only IF----you're using the new upgraded Yahoo (Beta version). Click Options>>then mail options>>and on the "general options" page (under "Messages settings")---check the button that says "Show all messages in a scrolling list" (with Preview Pane option) . THEN click "Save changes" in the upper left corner. That puts all your emails in ONE long scrolling list so you can delete them all at once. Then---"Select all"---and "delete". ************************************* However: Sounds like you're using the Classic version----you can only delete a page at a time, BUT you CAN assign more mail to a page. Just change the "messages per page" to 200 instead of 25. That's 8 times faster at least. Mail page>>options>>mail options----go down to and change the number in the box---then click "save" change. Now you can delete them page by page----200 at a whack

Click the check and press delete. Have fun :)

At like the very top it has a thing you can click and all the emails are Highlighted and when you click delete the entire inbox is deleted

Isn't there a little check box on the top? Just click that box and all the emails will be checked and then click delete. That should do the trick. I just hope it won't freeze or anything like that.

Click on the box: "select" and see there is whole checks on every emails and click the delete. Bud, am I clear to you?

there is a top square button. click on it and it will highlight the emails. erase it like that