1. Make sure to have legit copy of Rocksmith and Cherub Rock DLC 2. If none of the CDLC works, Validate the dll file with CFSM (This option is on the settings page of CFSM) 3. If some work and others don't, I would start with CFSM to repair the songs in question. The repair options I use personally are: Skip previously remastered CDLC, Add DD, Mastery 100% bug, preserve stats, adjust scroll speed, Fix Low Bass Tuning, Apply Default appid (probably the most important thing for your issue), and Process downloads folder. I use this repair operation to add any and all CDLC to my collection to ensure uniformity and game stability. hope this helps, good luck!