"A content database with the same ID already exists on the farm"

I am trying to restore a backup of our Production Database to our Test environment, and receive the error "A content database with the same ID already exists on the farm." after the restore operation completes.

After attaching the new Database to the new application I created for it, I cannot pull up the site.

How can I remove this duplicate ID? I believe the offending ID is in the SP_Config database's SiteMap table, but i am unsure if I should be removing anything开发者_运维技巧 from here. We also have a full test content DB that cannot be touched. Has anyone else had this issue?

Have you done this backup/restore previously from the PROD to TEST farms?

You may need to delete the previous content database from the TESTfarm if that is the case.