I have this project where I inserted a couple midi loops which created seperate tracks for each one.
 
I also inserted the si drum vst and a bass vst and a strings vst I played the notes live and recorded. I used groove clip looping on all the tracks the loop files and the live recordings with the vsts at 4/4.
 
However for some reason when I try to mix down the the project into mp3 or wav it seems like some of the tracks are missing and  only the track data I created gets exported and the rest of the audio is the piano ballad loop file and drum riff file I got from online you cant hear.
 
So basicly what I played on the mpc when using vsts mixed down however the midi loop files did not. ?? any ideas