Have finished upgrading to Windows 8.1 and my RAID-5 ReFS volume has NOT yet been recognized. It was not available in "This PC" after the upgrade... and was still not available after using the ReFS registry hack. After applying the hack and restarting the computer, the only change was the System Reserved portion of my C drive became visible. Under Administrative Tools> Computer Management> Disk Management, the drives in question are visible as a single RAID-5 volume but Status shows "failed", the file system entry is empty, and the drive letter is absent showing a red "x" icon. Currently downloading the latest chipset, SATA AHCI, and graphics drivers for my mobo. Will update once those have been installed. Anyone have any ideas? For more info--> Original post: Forum> Windows 8> "Seeking REFS advice"