After installing the latest version, and with the last version as well, rescanning does not find new CDLC; I can tell by the file count that the rescan only keeps rescanning the same list of files the program already knows, not all that's in the folder.

Some of the "extra" files may be for another version of Rocksmith. PC song files end in _p.psarc, MAC files with _m.psarc. Could be the difference. good luck