I came to the product as a switcher from the Windows environment in 2008. Lo and behold I was sorting email and came across a winmail.dat file attachment! Installing the trial, it was immediately resolved! I thought I'd wait and see if I missed it. Until recently, I'd not upgraded to the new version when I updated my OS to Mavericks. I've been a long time user of Letter Opener, going back to the OMiC days. The published price is that of an annual subscription. Once Letter Opener is installed, email attachments just work! 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. Letter Opener converts winmail.dat files on the fly, so you can actually see and use what the sender intended you to have. With Letter Opener in Apple Mail, the worry is gone. In those cases, you may miss important communications. 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. When this comes from an employer or client, it's even more frustrating. 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. Letter Opener extracts attachments from winmail.dat files (was OMiC).