Hi all!

I have encountered strange things with my XD3! I have many stiles and midifiles organised within different folders on the hard disk. While playing durring the winter holliday I noticed that on different midifiles in the same folder the bass track simply DISSAPEARD!!!! How could that be possible? I am still looking for the answer, but cannot find any resonable one!
Please help me find the reason of this strange problem.
Thank you!