Spanned Volume Disappears

[MnkyOf[-]ate]

Hello,

I am running Windows 7 Ultimate x64 and am using 3x hard drives. I am using an SSD to run the OS and 2x spanned 1TB drivers for media storage.

1. Samsung 840 EVO SSD: OS intalled
2. 1TB Western Digital Black (spanned: 1/2)
3. 1TB Western Digital Black (spanned: 2/2)

For some strange reason the spanned volume (assigned as E:\) keeps disappearing on me. It only seems to disappear if I leave the computer idling for a while. The volume always reappears if I reboot the computer. I have tried launching disk management, sometimes it shows 1/2 volumes as offline but I am unable to reactivate it. Other times there is no listing of either driver in disk management, so I launch diskpart and neither of the 2 volumes are shown either.

chkdsk says the volumes and partitions are healthy, and SMART is not showing any issues with the overall health of the drives. I have also disabled power saving features in windows and in the BIOS thinking maybe the drives were going to sleep and not waking up again.

I'm quite confused. Does anyone have any ideas what else to check?
Thanks in advance!