I'm using SQL-2005 on Windows 2003. Under Server > Security > Logins when I display the security properties for a user I get the error message above. It seems to happen on all the users. The General and Server Roles tabs work ok, but when I click on User Mapping I get the error message. Then what appears to be the correct information for the user displays.
What's causing this error? Must be some kind of system catalog corruption, I'm thinking. Maybe an old database that got deleted improperly or something like that. Any ideas how to fix it?