Question : Can't open this item. Your Digital ID name can not be found by the underlying security system

I just got Autoenrollment working for our Exchange certification server and the first user that got updated is now getting the following error while trying to open a encrypted email: Can't open this item. Your Digital ID name can not be found by the underlying security system

Exchange 2003 and outlook 2003.

Answer : Can't open this item. Your Digital ID name can not be found by the underlying security system

Greetings:

Have you loaded the user certificates on the machine?  Published them to the GAL?  Are you using hard or soft certs.

http://support.microsoft.com/kb/q258527/