The messaging interface has returned an unknown error

This is an error I have ran across more than a few times in my IT support job. I hope this will help someone from being frustrated by the same error. I get it most often when a user attempts to print a delegated calendar (shared calendar) in the daily style. The “error” is actually a permissions problem with the users task pad. Here is the solution to print the calendar:

This is from the Microsoft Knowledge base article:912803

1. Select Print from the File menu
2. Click on Page Setup
3. On the format tab, click to clear the task pad checkbox
4. Click Ok
5. With the daily style selected press OK to print the calendar.