piano sound is layered
I use Garageband to record rehearsal trax for my students using a midi keyboard to play their parts. Today I downloaded and installed the new version of Garageband 10.0.2. But for some reason, the piano sound is layered with a sort of wave synth sound that I can't get rid of. I did a little online research and different people suggest throwing away different things, but I can't figure it out. Any suggestions? I even opened up the old version but it is infected with this problem now too. Thanks!
MacBook Pro (13-inch Mid 2009), OS X Mavericks (10.9)