Installing CDLC requires a one-time setup to "patch" your game so it recognizes unofficial files.
If you want CDLC to work without hiccups, buy Cherub Rock . It is a $3 key that unlocks the entire custom universe. rocksmith cdlc
Rocksmith CDLC (Custom Downloadable Content) refers to community-made song files created for and the newer Learn and Play Edition Installing CDLC requires a one-time setup to "patch"