Problem: Restored a backup of a database from SQL Server 2005 onto a local SQL Server 2008 instance. The process worked but when trying to open the diagrams group, it throws the following error:-
‘Database diagram support objects cannot be installed because this database does not have a valid owner. To..’
Solution: Run the following SQL Script on the database.
EXEC sp_dbcmptlevel 'YourDatabaseName', '90'; go ALTER AUTHORIZATION ON DATABASE::YourDatabaseName TO "sa_or_valid_user_who_isnt_logged_in" go use [YourDatabaseName] go EXECUTE AS USER = N'dbo' REVERT go