Let's install Windows 11 on incompatible hardware

spapakons said:

I was talking about a Legacy BIOS installation, not a standard UEFI mode installation. To do a Legacy BIOS installation you must create an MBR USB flash drive. I will check with a virtual machine using the 25H2 ISO and the 26H2 ISO and report back.

Click to expand...

I previously tried a BIOS/MBR installation using the method you described (see the image below).



In the virtual machine, I used a Windows 11 26H2 ISO created using the Media Creation Tool. The installation media supports both UEFI and Legacy BIOS boot. I bypassed the Windows 11 system requirements using a .reg file.

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By the way, VMware Workstation Pro also allows booting from a physical USB flash drive in UEFI mode, although doing so is not as straightforward as booting from an ISO file.

How to perform a clean install of Windows 11 in VMware Workstation Pro using a physical USB flash drive as the boot device

1. VM > Power > Power On to Firmware
2. VM > Removable Devices > the name of your USB > Connect (Disconnet from Host)
3. Boot Manager > Enter setup > Boot from a file
4. Select the correct entry:
   • USB created using the Media Creation Tool: ESD-USB
   • Rufus: RUFUS_BOOT
   • Ventoy (Secure Boot must be disabled): VTOYEFI
5. Navigate to the /EFI/BOOT directory.
6. Select the BOOTX64.EFI file.

Note that the USB flash drive takes longer than usual to boot.

spapakons said:

I was talking about a Legacy BIOS installation, not a standard UEFI mode installation. To do a Legacy BIOS installation you must create an MBR USB flash drive. I will check with a virtual machine using the 25H2 ISO and the 26H2 ISO and report back.

Click to expand...

I wanted to confirm if I can do a Legacy BIOS mode (MBR disk) of Windows 11 26H2 with a single NTFS partition. So I created a new virtual machine in VMWare Workstation Pro 17.5 for which I selected Windows 7 64-bit as the Guest OS, so it would allow me to choose BIOS over UEFI firmware. I selected BIOS, then out the Windows 11 26H2 ISO in the virtual DVD drive and booted it. I then pressed SHIFT+F10 to run diskpart and create the single NTFS partition using this code:


The convert mbr command converts the disk to MBR if it is GPT, otherwise does nothing. The active command makes the partition bootable, but Setup should do that anyway.

I then proceeded with Setup. I got an error that the CPU was not compliant, I had no TPM or Secure Boot. I pressed SHIFT+F10 once again and executed regedit to open Registry Editor and apple the Registry patch to bypass compatibility check. This time Setup proceeded and then got me to the disk selection screen. I just clicked on the single NTFS partition of the virtual hard disk and clicked Next to begin. Setup started installing without any complain, so it DOES work for a Legacy BIOS mode installation on an old unsupported computer without UEFI firmware. I will post screenshots once finished. I also confirmed that the good old Registry hack from 2021 for Windows 11 21H2 still works in all versions up to 26H2.

For anyone interested here it is:

- When the Registry Editor shows up, find this key:
HKEY_LOCAL_MACHINE\SYSTEM\Setup
- Create new key LabConfig inside the Setup.
- Create DWORD (32 Bit) BypassTPMCheck and set to 1
- Create DWORD (32 Bit) BypassSecureBootCheck and set to 1
- Create DWORD (32 Bit) BypassRAMCheck and set to 1
- Create DWORD (32 Bit) BypassCPUCheck and set to 1
- Continue the installation until it finished.

EDIT: Legacy BIOS mode Installation of Windows 11 26H2 completed successfully. I made sure the virtual network adapter was disabled and at network screen I pressed SHIFT+F10 to open a Command Prompt. Then I tried the command oobe\bypassnro which worked! After making changes to the system, it restarted back to OOBE stage and this time at the network screen there was the blue text "I don't have an internet connection". I clicked on that and I was allowed to create a local Administrator account! After I was at the desktop, I opened Disk Management to check, it seems like Setup created the recovery partition, but not the small system partition. I can just delete the recovery partition and make the Windows partition take the whole disk, but I will lose the recovery options. I would only do that for a very small disk, less than 64GB.




Conclusions:
- The Registry hack to bypass compatibility check to clean install Windows 11 on an unsupported computer still works on version 26H2.
- Windows 11 26H2 can also be installed on an unsupported computer with Legacy BIOS without UEFI firmware, without TPM, without Secure Boot. Only requirement a CPU with at least two cores and SSE4.2 instructions support. All physical CPUs with SSE4.2 instructions have at least 2 cores, but when creating a virtual machine make sure it has at least 2 cores or you will get a CPU compatibility warning.
- The oobe\bypassnro command didn't work on the original 25H2 ISO from October 2025 because the respective file was removed, but it DOES work on 26H2, probably the file isn't removed.

Celery said:

I previously tried a BIOS/MBR installation using the method you described (see the image below).

View attachment 184823

In the virtual machine, I used a Windows 11 26H2 ISO created using the Media Creation Tool. The installation media supports both UEFI and Legacy BIOS boot. I bypassed the Windows 11 system requirements using a .reg file.

---

By the way, VMware Workstation Pro also allows booting from a physical USB flash drive in UEFI mode, although doing so is not as straightforward as booting from an ISO file.

How to perform a clean install of Windows 11 in VMware Workstation Pro using a physical USB flash drive as the boot device

1. VM > Power > Power On to Firmware
2. VM > Removable Devices > the name of your USB > Connect (Disconnet from Host)
3. Boot Manager > Enter setup > Boot from a file
4. Select the correct entry:
   • Windows (USB created using the Media Creation Tool): ESD-USB
   • Rufus: RUFUS_BOOT
   • Ventoy (Secure Boot must be disabled): VTOYEFI
5. Navigate to the /EFI/BOOT directory.
6. Select the BOOTX64.EFI file.

Note that the USB flash drive takes longer than usual to boot.

Click to expand...

Try creating the USB flash drive again, this time use Rufus and make sure you switch to MBR (default is GPT).