Just Bumping this as this has just happened again after about a year.
So my computer is left on all the time, I come back in from work and can't find my Raid Volume.
I open "Disk Management" and I see this...
Nothing in the event log.
I used Active Partition Recover to recover the volume and all is well but still can't explain why this happens.
Running RST: 184.108.40.2066
Windows 7 x64
Thanks for coming back to the community.
This problem might be related to the on-board RAID controller, the chipset itself or the RAID BIOS version is out of date.
You may need to look for a BIOS update that contains an updated option ROM and install the latest Intel® Rapid Storage software version 12.9