After upgrading to Parallels 9 update for Mavericks whenever I attempt to share a web page via Share => Email this page, Parallels & Windows OS begins to load. I cannot find any preferences to revert back to Mac Mail as the default email program.
Thanks!!!! I was just preparing to send a trouble report to Parallels. This swithch must have happened via the upgrading to Parallels 9 with the latest build for Mavericks. All is well after reseting the Mac Mail default as you suggested.