If you encounter this

Could not obtain information about Windows NT group/user , error code 0x5.

When you try and CREATE an ASSEMBLY, you might think well I'm not connected as that user. The user it sqawks about is the database owner.

I run on a laptop and often find myself not connected to the domain (although I can still log in with cached domain credentials). When I create a database the database automatically becomes owened by my domain account so when I then try and create an assembly it sqawks because it can't verify the domain account that owns the database.

The simple way around this is to create a sql user account and change the database owner to that user.