Then you really need to contact ASrock and tell them so they can send you a updated BIOS. There's absolutely no reason to enable RAID when not using it. You have two new BIOS updates for 2015, 1.30 and 1.40. How could you install the RAID driver for RST in windows, when you didn't create an array with either the OROM or UEFI. Impossible. Can you post who responds to your support, I know most all of the TSD, as I have been building ASrock for a long time, and have built several low end B,H series for people who didn't have the money for Z, but never run into the problem you state. This board also doesn't state it supports RAID, and there is no RAID option in the BIOS, sure is strange. Here is what your manual shows for storage options. SATA Mode Selection IDE: For better compatibility. AHCI: Supports new features that improve performance. NO RAID OPTION. Maybe you made a mistake and have another board.
This could be the main reason. I did not install any Windows driver for the RST. Just had to enable Intel RST in BIOS. In Windows 8, I did not enabled it. And yet no problem. Perhaps because I was using the 1.30 firmware and introduces a bug in 1.40.