Earlier I wrote about an Exchange 2000/2003 hotfix that resolves Windows Vista/OWA message editing problems. Well, after I applied the hotfix to our Exchange 2003 server, it took all of about an hour before I had two complaints come in from users about receiving blank emails.
KB 919238 describes a known issue with the hotfix and the Microsoft Entourage email client where an OWA user sends or forwards a message to an Entourage user, and the Entourage user sees a blank message body.
KB 919238 states if you encounter this problem, uninstall the previous version of hotfix 919829 from your Exchange server, then install the updated version of hotfix 911829, which is 6.5.7651.60.
The updated hotfix does require Exchange 2003 SP2, but does not require a server reboot.