I've been using Rocksmith 2014 CDLC for about a year now and this has never happened to me before.
Just the other day all of CDLC disappeared. I have already bought Cherub Rock on steam, downloaded D3Dx_42.dll, and downloaded the mod installer, but the CDLC still will not appear. I have also tried unblocking a couple of the songs through files, and redownloaded a few of them but that didn't work either.
All of my CDLC are still in DLC folder on the Rocksmith2014 file on my computer as well, as well as Cherub Rock.
I'm not sure if this has happened to anyone else, but it's pretty annoying, considering it has wiped out 3/4 of my songs on Rocksmith 2014.