A good error message in my opinion provides enough information for the user or administrator to determine likely cause. It doesn’t have to be THE cause. Just something I can try changing and see if the problem disappears.
For a while now, Outlook was telling me the “Operation Failed” in a toaster pop-up. O… kay…. After some initial poking around I was able to discover the failure was because of an RSS feed. No mention of which one. The problem didn’t go away, so I decided to delete the feeds to no improvement. So I had no RSS feeds and was still getting the error about the RSS feed. So I looked in the Deleted Items to see which feeds I should add back and noticed one I didn’t deleted. So I permanently deleted all of them.
No more errors.
So the problem was: I deleted an RSS feed. Send/Receive was unable to write new results to the deleted feed, so it told “Operation Failed.”
No, Microsoft, you are the fail.