This occurs when the software is not communicating properly with the hardware in the unit. The main causes are that one of the plug-in cards is not seated properly to the motherboard, the software is corrupt, or the hard drive has bad sectors. First, try powering the unit down and reseating all the cards. Second you can try reloading the software. Finally, if the problem still persist, it is recommended a new hard drive between 80G to 200G be installed and software is reloaded. Note: These HD generators read/write to their hard drive 24/7.