I just started getting an error window with "Unspecified Error" in MS Sql Server Management Studio 2005. I get this when trying to Create a New Table in a DB or Right Click > Design on an existing table. I am able to open up a new connection and query the DB without any problems. The error message obviously is no help. Any thoughts on what is the cause and how to fix this?
I realize this answer is a little late in coming, but I just ran into this same issue.
Strangely enough, the error seems to go away if I use SQL Server Authentication rather than Windows Authentication. If you don't have that as an option or that doesn't work for you, I suppose you'll need to resort to old fashioned SQL statements.