Problem with new Sansa Clip 8G + freezes when using the menu button to lock player

I recently purchased a Sansa Clip + 8 GB. I updated the firmware and installed my music on the device. The problem I am having is when I push the the main menu button to lock the player it freezes up after 25 seconds. The only way I can get the player to work after it freezes is to hold the on off button for 15 seconds. Before I send it back for another one is there a fix to this problem.

thank you