I hit an interest problem recently when users started getting errors when they tried to add items to Discussion boards that had been working previously. The error message they were getting was a fairly generic message informing them that the list does not exist.
I grabbed the list guid from the url in the Sharepoint logs that matched this Correlation ID, a
SELECT * FROM AllLists WHERE tp_ID = 'AAFC8333-CC4B-4A4A-83D9-CE14AE17EE76'
promptly brought back the details of a list which proved that it did in fact exist.
I did a bit more digging but didn't get very far so I hit google but did not find much help there. Eventually after googling obscure errors in the Sharepoint Logs I came across this
page which talked about how a previous CU had caused their Discussion Boards to break. They had troubleshooted the problem with Microsoft who provided this script:
UPDATE awp SET awp.tp_ContentTypeId=0x0, awp.tp_BaseViewID=0
FROM AllWebParts as awp
JOIN AllLists as al
ON awp.tp_ListId=al.tp_Id
WHERE al.tp_FeatureId='00BFEA71-6A49-43FA-B535-D15C05500108'
AND al.tp_ServerTemplate=108
AND awp.tp_BaseViewID=3
AND awp.tp_View IS NULL
GO
I ran the script on my testing box and it fixed the problem, I then ran it on my production DB and "jobs a good un"!!