I too am having the same problem. I have never dropped my Zune, and when my player started to reboot, I put the lock on. The device is in my jacket pocket and is not disturbed. Like yourself, the only thing that changes is maybe slight movements in the headphones, however I don't use the Zune headphones, but I have upgraded to a $99 pair of V-Moda headphones, and I seriously doubt there is a problem with them. Today it happened about 5 times within one hour, other times it has happened less frequently, and sometimes I have no problem at all. I am not able to return mine to the store because I got it as a Christmas gift and do not have the receipt. Does anyone have any suggestions?