SQL Server 2005 error: Database diagram support objects cannot be installed because this database does not have a valid owner April 17, 2009

With SQL Server 2005, when you get the error message:

“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.”

Even when the database does have a valid owner, then the database compatibility level is probably set to lower than 90, this can happen if you restore a database created in an earlier version of SQL Server. To fix it run:

sp_dbcmptlevel @dbname=’MyDatabaseName’, @new_cmptlevel=90

Visual Studio error: The project file ‘ ‘ has been renamed or is no longer in the solution April 1, 2009

You get this error when trying to build a Web Project which has a reference to an assembly it can’t find. To fix it:

1. Open the property pages for the site
2. On the references tab remove any references with ‘unavailable’ next to them
3. Re-add the reference and build