Letter Opener extracts attachments from winmail.dat files (was OMiC). When using Apple Mail, if you've ever received an e-mail that included an attachment called winmail.dat, you know the frustration of not knowing what was sent to you. When this comes from an employer or client, it's even more frustrating. That winmail.dat file may only be the rich text format or it could contain an important graphic, calendar entry or invitation, task, address book contact, Microsoft Outlook Note, or nested messages. In those cases, you may miss important communications.
With Letter Opener in Apple Mail, the worry is gone. Letter Opener converts winmail.dat files on the fly, so you can actually see and use what the sender intended you to have. There's no fuss with Letter Opener, no need to drag the winmail.dat file onto another application or call upon several programs to help you. Once Letter Opener is installed, email attachments just work!