Troubleshooting... Cannot Preview Email

Issue:

While using a MAPI email plugin with Windows Vista/7, the default email client (Outlook, Windows Mail, etc.) will not preview the message if it is already running on the machine.  An "Unknown Error" is returned in most cases.

Solution:

This issue is due to access rights differences between the host application and the email client.  If for instance you are running Delphi in Administrator mode and have Outlook running in User mode, you will receive the error.  To solve the problem, simply be sure each application is running under the same security context.