SQL - Database diagram support objects cannot be installed because this database does not have a valid owner

The full error message reads as:

"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."





And the reason is obvious that the account you are logged in with, does not have the ownership of the database. This can happen because of many reasons, i.e., if you change your computer name or if you are logged in with a different account than the one you used to create the database.

What ever the reason is the simplest solution to this problem is to make "sa" the owner of the database. This way, it wouldn't matter if you change your computer name, move your database to a different computer, etc. Issue the following statement as:

ALTER AUTHORIZATION ON DATABASE::MyDatabaseName TO [sa];