The messaging interface has returned an unknown errorOkay, a simple search turns up the following Microsoft KB articles, but they are not relevant:
- KB 275186: "The messaging interface has returned an unknown error" error message when you forward a message in Outlook 2000 SR-1.
- KB 813517: "The messaging interface has returned an unknown error" error message when you create a new e-mail message or forward a message in Outlook 2002.
- KB 892450: You receive a "The messaging interface has returned an unknown error " error message when you try to use Outlook to make a change to a recurring appointment in the Calendar of your Hotmail account or of your MSN e-mail account.
- KB 814441: Error message when you try to read or to delete e-mail, or when you click "Send/Receive" in Outlook: "An unknown error has occurred" or "Messaging interface has caused an unknown error"
Once, and only once did we get an error indicating permissions problems on the task list folder before the above mentioned error.
So, when printing the calendar view, we went to the Page Setup button, and disabled printing the tasks list.
So far, we haven't been able to find out just where the permissions conflict is yet.
But, they are happy about being able to print out their calendar again.
Honourable mention to the following who provided the key to figuring out how to get things going again:
Experts-Exchange: The messaging interface has returned an unknown error.
MCSE.MS: The messaging interface has returned an unknown error.
Microsoft Small Business Specialists