If you try to use the database diagram feature in SQL Server Management Studio and the owner of the database is a domain id but you are disconnected from the domain (notebook users!), you’ll get an error like this:
“Database diagram support objects cannot be installed because this database does not have a valid owner. To continue, first use the Files page of the Database Properties dialog box or the ALTER AUTHORIZATION statement to set the database owner to a valid login, then add the database diagram support objects.“
What you need to do is change ownership of the database:
/* replace the database name parameters with [CTRL]+[SHIFT]+[M] */
use master
go
ALTER AUTHORIZATION ON DATABASE::<Database_Name, sysname, Database_Name> TO “sa”
go
use <Database_Name, sysname, Database_Name>
go
EXECUTE AS USER = N’dbo’ REVERT
go