User guest does not have permission to run DBCC checkprimaryfile (SMSS)
Have you seen this post on the MSDN forums?

User guest does not have permission to run DBCC checkprimaryfile

One possible solution proposed in that thread is to run SSMS as an administrator.

The other option is to make sure that the user account you're using to the connect to SQL Server:


has a login setup on the instance
has the appropriate permissions for attaching a database (CREATE DATABASE, CREATE ANY DATABASE, or ALTER ANY DATABASE)