Windows 8.1 & Windows 10 dualboot a big struggle

Question

Hi everyone,

I know this might be a bit of a stupid/weird question, as both systems are now seen as unsupported.

I’ve been messing around with my pc lately and I thought it would be a fun little project to dualboot Windows 8.1 along with my main Windows 10 install. I’ve run into multiple issues previously which on itself made sense but I’m currently in a bit of a dead end.

Every single time I open the 8.1 setup off a flash drive, only one partition shows up which is my data drive (D:, MBR, on a different disk.) My other disk which is gpt and has all of my partitions on it will not show up no matter what. If I f10+shift and then use disk part it also doesn’t show up in there.

The weird part is, on Windows 10, if I’m in the recovery menu and open the 8.1 setup on top of the recovery cmd all my drives show up. I’ve tried installing 8.1 from there but it throws a really quick bsod (like seriously not even a second) and I got inaccessible boot device along with another bsod but I could not read it whatsoever. This is on the first boot after install.

Whenever I try to manually install and mount the image through cmd no matter if it’s in the recovery cmd or my main 10 cmd, it also just bsods on me with inaccessible boot device. I’ve deployed manually thrice by now.

I have secure boot disabled, AHCI on in stead of RST or whatever could go there, and my image is not corrupted in any way, shape, or form. I do want to mention, my pc is a Acer Predator Orion 5000, so it is a newer pc but it technically should work, the hardware is still compatible even if it’s on the edge. I figured that maybe it bsod’d because it didn’t have NVMe drivers, but after injecting them into the image through cmd it physically can’t be that.

I’m really lost and I can’t find anything on this. Does anyone know what I could possibly do? I want to install them on the same disk. I don’t want any virtual machines or other hard drives I can attach.

Thank you all!

Answer 1

Hi marieayoo,

Welcome to Microsoft Q&A!

I understand how this can be frustrating. You’ve already tried the right steps, but the issue seems like hitting a dead end. Since Windows 8.1 and 10 are no longer supported, options are very limited.

Windows 8.1 Setup runs on an older WinPE environment that lacks modern storage controller drivers. The missing piece is usually the storage controller (RST/VMD/AHCI), not the NVMe driver itself.

On newer desktops, including NVMe‑only systems, Windows 8.1 likely doesn’t have a compatible storage driver. Without it, installation on the same NVMe disk isn’t possible by design. If you want to continue experimenting:

1 - Make sure the Windows 8.1 installer is booted in UEFI mode

• Reboot and open the one‑time boot menu (F12 / Esc)
• Select the USB entry that explicitly starts with UEFI:
• Do not boot a Legacy or non‑UEFI USB entry.
• Start Windows 8.1 Setup and check if the GPT disk appears.

2 - Load the correct storage controller driver during Windows 8.1 Setup

• In Windows 10 system, open Device Manager.
• Check Storage controllers and IDE ATA/ATAPI controllers.
• Note the exact controller name (e.g. Intel RST, VMD, SATA AHCI).
• Download the matching Windows 8.1 storage / F6 driver (Acer/Intel)
• Extract it until you see .INF files (not just an .EXE)
• Copy the extracted driver folder to a USB stick.
• Boot into Windows 8.1 Setup > Load driver > Browse.
• Point to the folder containing the .INF files found above.
• If the driver is correct, your GPT/NVMe disk would appear

If installation succeeds but BSODs on first boot, that confirms the installer could see the disk, but Windows 8.1 still lacks the boot‑critical storage driver. Go back to #2 and try a different driver variant that matches your firmware mode.

If that fails, the final other options you can consider include installing Windows 8.1 on an older SATA SSD (separate controller path), or running it in a virtual machine.

However, if none of the above helps, I’m sorry to say but it’s likely impossible to create what you want. Since both the versions have been out of support, there’s not much you can do.

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Answer 2

I’ve found the solution (apparently switching ahci and rst in between each other twice helps? idk) and I managed to install it. I couldn’t find any drivers for it tho. Thank you!