Late last Tuesday the main Windows 8.1 machine that I use for work notified me that there were 5 new updates available.

as soon as I had a moment I allowed the updates to go ahead.

this machine is running i7 intel cpu with 24GB of memory, a Samsung Pro 512GB SSD for the system drive and 4 WD2TB RE4 hard drives in a parity storage space in fixed format utilizing all the available disk space.

the operating system is Windows 8.1 Enterprise with the bits downloaded from Microsoft Volume Licensing site and activated with a volume license setup key.

I came back to this machine several hours later and it was still installing the last update.

I couldn't wait, so I shutdown the machine by right clicking the Start button initiating a shutdown.

I left it at the shutting down phase and went home.

the next morning I found the machine still at the shutting down phase and unresponsive to any keyboard or mouse input.

not having any other options, I reset the machine and tried to reboot.

the machine started the boot process, the hard drive lights on the 4 WD2TB cycled as the operating system enumerated them and then the system hung on one of the WD2TB drives with the hard drive light on, and the main activity light solidly on.

the 4 WD2TB drives are in a drive cage that has an activity light for each drive.

the dot circle that windows 8.x uses for the hourglass kept on spinning and the drive light solidly on one drive and main drive activity light also solidly on.

I waited several hours for the machine to finish booting, but it was hung.

so I pressed the reset button and let the machine try to boot and again the same condition, hung on one drive but this time the drive was different than the first time.

so I thought that something was wrong with the drive(s) so I shut the machine off and pull the hung drive from the drive cage.

this time the machine completes the boot and lets me logon to the desktop, but the parity volume based on the drive managed by storage spaces doesn't come online.

I open storage spaces and it shows that the 3 drives are ok, but the volume is not accessible because a drive is missing.

what gives with that? it is parity right? it should tolerate a single disk failure all day long and the volume should be ok.

apparently there are exceptions to this. who would have guessed?

I shutdown the machine and added the drive back and rebooted. and it hangs again on a different drive.

I press reset and turn off the machine and remove the other drive that had just now hung, and the machine boots just fine, but the parity volume is still inaccessible and it is asking for the 4th drive. the drive that had originally hung is showing green and fine.

I checked the S.M.A.R.T on all drives and they were clean. the drives are less than six months old.

no matter what the machine will not finish booting with all four drives connected. it hangs on one of the drives.

so I figured that either the cage or the motherboard had a problem.

so I add a blank SSD to another machine with the same type of intel hard drive controller and build it with Windows 8.1 Pro with all the patches and updates.

I then connect the 4 WD2TB drives directly to the motherboard without a drive cage, just SATA cables directly to the motherboard. brand new ones at that.

I boot the machine and what do I get?

the new machine hangs on one of the four drives just like the original machine.

it will boot with 3 drives, but will hang on 4, and it will not bring the volume online with only 3 drives.

can someone shed some light on this?

I have over 5TB of data on that volume and I was fully confident that with parity it was protected!

what are my options for recovering this volume?

what tools can I use to further narrow down the problem?

any insight on this situation would be greatly appreciated.

now I have to re-think the storage spaces options for disk drive volumes and storage if something like this can happen.

under what conditions is parity really not parity? this is critical!

could one of the updates be the cause?

I'm in the same problem. My 4 x 1TB Parity drive started hanging suddenly. I managed to get PowerShell and disconnect the problem disk. ("disconnect-virtualdisk" command.) Then the system works fine with no hang-up while the volume is off-line. When the drive is re-connected ("connect-virtualdisk"), the system hangs again whenever it tries to access the volume. The storage spaces control panel shows it's "regenerating". However, the progress stuck to 0% forever. It looks like an OS bug that hangs even before the parity regeneration kicks in. (Probably, due to a slightly corrupted disk metadata?)

ReclaiMe Storage Spaces Recovery (http://www.storage-spaces-recovery.com/) managed to see the files while the volume is not mounted. Unfortunately, recovering data is not free.

The free version has a feature creating a VHDX disk image out of the problem Storage Spaces driver. It seemed working fine with small volumes. But, the feature is somewhat buggy and fails on the large volume I have. (Mine is 2.7 TB.)

Wondering Microsoft ever reorganized this issue. :(