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Windows won't boot. Requested system device cannot be found


New member

Desktop computer, ASROCK UEFI, Windows 8.1. x64, SSD disk. disk is healthy…

So BSOD appeard on my computer saying that it encountered a problem. After restart it says: File: \EFI\Microsoft\Boot\BCD. Error code: 0xc000000f. Few times i got different error message: File: \Windows\System32\drivers\ACPI.sys. Error code: 0xc0000242

After trying to recover it with bootrec /fixmbr…fixboot…rebuildbcd… and writing Yes to add installation to boot list it says: the requested system device cannot be found.

I tried making the disk active and it didn’t help. Every solution i found on google end up the the same.

One possible problem/solution i found is that the EFI partition is lost or corrupted and i need to fix/recreate that.

Diskpart says my windows disk has 2 partitions: Partition 1 - Primary-729mb-offset 1024mb… Partition 2 - Primary-232gb-offset 731mb

I don’t see EFI written anywhere and it says all disks are NFTS (btw i have no idea what all those terms mean). In solutions i found most of them have one 500mb partition… i guess that’s that 729mb partition in my case or what?

Any ideas what i have to do without losing everything?
Last edited:


Staff member
Hello, welcome to CF 👋

It looks like you’ve done most of the stuff I would suggest already - really it would now be time to nuke the drive and install a fresh copy of Windows but you mentioned you have data you need to recover.

The only other thing to try is using bcdboot instead of fixmbr.
This page gives you an overview of the process. Note that it’s easy to potentially slip up with diskpart so be sure to double check before pressing enter.

In which case - I’d suggest, if you can, creating a Linux live disk and mounting the drive to access the data, backing it up to another external hard disk, online cloud storage or similar.


New member
Windows Won't Boot? 8 Fixes to Get Your PC Running Again.

(i). Try Windows Safe Mode.
(ii). Check Your Battery.
(iii). Unplug All Your USB Devices.
(iv). Turn Off Fast Boot.
(v). Check Your Other BIOS/UEFI Settings.
(vi). Try a Malware Scan.
(vii). Boot to Command Prompt Interface.
(viii). Use System Restore or Startup Repair.