My SX920 was HANG

[Doffi]

Dear All,
I opened  style creator for manually synchronize some voice styles that had no sound. When I open the style creator page there was no problem, but when I pressed the Rec channel, the keyboard suddenly hang. I had to do a hard shutdown to restart it again . What could be the possible causes of this? For information, the keyboard's hard disk is only about 50% used. I have experienced this hang several times."

Thank you,