having just finished updating to win 8.1 on a clean install of win 8 pro, I decided to setup storage pool. I used the wizard, selected each of my two 3 tb HDD and clicked 'next' the wizard came back with 'not able to set up a pool' and only showed one of the two drives. I opened disk management, to find that the second drive had disappeared totally.
I went to device manager and there it is, I see my SSD and both HDD.
I uninstalled both of the HDD and then rebooted (cold) went back into device manager, and both are registered, and both are active and reported as working. I checked for driver update, but drivers are the latest available.
I opened disk manager and can only see the ssd and one of the two drives. There is nothing else in there to do anything with.
Well I found out what happened. Just in case anyone else suffers the same thing this is what occurred. Why it occurred I don't know.
For some reason as the wizard was formatting one of the two disks an error occurred that resulted in the disk being wiped but not being reformatted. When it completed it could only see one of the two disks and therefore could not make a mirrored pool.
None of windows tools could see the disk to do anything with it. At this point I did not know the original formatting had been wiped.
Re boots did nothing and no error message came up, the disk was simply "gone".
The fix came through Linux. I downloaded a Ubuntu image (14.04) burnt a live disc, and booted into the Linux system using the "try Ubuntu" option. I then used Gparted the Linux partitioning tool. With this tool I could see the disk, and that was when I could see it was unformatted. I did a full reformat to NTFS and then backed out of the live cd.
Re booted into windows and voila there was the disk, and storage space was able to be created without further issues.
Again not being a tecchie, I don't know why it occurred or why there was no way to fix it from within windows. maybe it was a freak, but anyway that's the fix for me. Hopefully it will help someone else one day.