@cozy1 I am trying to create a backing track (which I think is the cause in itself). Process was as follows: - Created EOF project with an MP3 file - Added a simple bass track (a C major scale in the beginning only) - Added lyrics (proving root note guidance) Plays fine in EOF, saved then opened Rocksmith Song Tool Kit - Added the vocals and Bass file - Applied the song information as required - Added the guitar.ogg created by EOF Hit Generate - then error occurs at the second stage in Wwise. I let RSTK create the preview file (usually) and I am only creating CDLC for the PC. I have made a number of them already, its just this one that gives me an issue. As a test a supplied a different ogg file from a previous CDLC I created just to see what happens and it then worked. I suspect its because I am trying to create a backing track with vey few notes apart from the scale in the beginning, tried also adding a closing note but it did not help. The workaround is 'working' for me. I am just going to create a small wem file next I think.