I would create a bootable USB flash drive or DVD of Kyhi's recovery drive:
Windows 10 Recovery Tools - Bootable Rescue Disk - Windows 10 Forums
See if the drives are readable when you boot the computer from it. Definitely a backup solution large enough to make backups onto is a must have! If the drives are readable in Kyhi's recovery drive, you can use the Macrium Reflect program included on his drive to make backup images of the hard drives. Then you can troubleshoot further by reformatting the hard drives without the "quick" to do a surface check of the drives while formatting. If you have bad sectors, I would recommend replacing the installed hard drives.
If the full long format of the drives comes back OK, then you can restore your backup images to the installed drive and chalk it up to the infamous Anniversary update glitch. I think that what happened with that is that something in the Anniversary update is not compatible with certain parameters used when partitioning some drives and simply backing up the drives with bootable software that is compatible, reformatting the drives, and restoring the backup images fixes it.