Second HDD disappears

[tomshd4jim]

I have a 3 year old HP Pavillion and added a new HDD. I bought the enclosure and added the SATA drive no problem, but every once and a while when the laptop is on say over night it disappears. I reboot and it is back again. Is the a filter like when a CD/DVD is lost or does anyone know what is up. Why does it seem to disappear?

 

[Hawkeye22]

It may be having problems waking from sleep mode. You can try adjusting your power settings and tell it not to let your drives go to sleep.