My earthlink e-mail is continually downloading--thousands of e-mails downloaded to my Mac three times and counting today

I'll assume that this is a POP account.

Back up all data before proceeding.

Triple-click anywhere in the line below on this page to select it:

~/Library/Containers/Mail/V2/MailData/MessageUidsAlreadyDownloaded3

Right-click or control-click the line and select

Services ▹ Reveal in Finder (or just Reveal)

from the contextual menu.* A folder should open with an item selected. Quit the application if it's running. Move the selected item to the Trash. Relaunch the application and test. The messages will download one more time, but then should stop.

*If you don't see the contextual menu item, copy the selected text to the Clipboard by pressing the key combination command-C. In the Finder, select

Go ▹ Go to Folder...

from the menu bar and paste into the box that opens by pressing command-V. You won't see what you pasted because a line break is included. Press return.

Open the Library folder in your home folder by holding down the option key and selecting

Go ▹ Library

from the Finder menu bar. Navigate in the usual way to the item indicated above.