I was looking at some of the "search" key phrases that my web site is getting briefly this morning. A while back, I posted about this useless error that Outlook was giving me.

"the messaging interface has returned an unknown error"

After posting, a commenter believed that it was simple enough and that restarting Outlook would solve the problem. I find it interesting that I'm getting a number of hits on the page -- more than likely looking for help, not because they want to see my imaginary witty banter. Well, I could hope.

They're likely searching for help that Microsoft did not provide when the error dialog is shown. Solution is still simple: (File -> Exit, then restart outlook from your Start menu). Sorry, but I don't know what specifically causes the problem. Network glitch, sun-spots, static discharge, etc. It doesn't tell me either.