Have you ever tried to send an attachment to someone, only to have that person tell you that the only thing attached to the e-mail was a file called Win.dat? This usually happens because you are trying to send your e-mail through Outlook’s Rich Text Format, which some e-mail systems don’t support. To make sure that file gets through unscathed, just select Tools, then Options, and then the Mail Format tab. Next to Compose in this Message Format, choose Plain Text. You can always go back and change it back to Rich Text Format later.

If the recipient still can’t open the file, Donna Payne offers this tip: open up the recipient’s contact, right-click on the e-mail address, and select Properties. Then:

  • In Outlook 2002 and 2003, next to Internet Format, select Send Plain Text Only
  • In Outlook 2000, de-select Always Send To This Recipient In Microsoft Exchange Rich Text Format