Elitebook 850 G4 won't boot with MBR disk. Please help. Thanks !

[itsarinya]

Hello eeveryone,

I do need your help.

My Elitebook 850 G4 runs on a factory GPT disk.
I wanted to replace the GPT disk with an MBR disk with Windows already installed, but the PC won't boot.
Could you help me? Please.
Thank you in advance.

Itsarinya

[Paul_Tikkanen]

Hi:

You have to go into the BIOS disable secure boot and enable legacy mode.

With legacy mode disabled and secure boot enabled, the PC can only boot from GPT-formatted drives.

Here's the link to the BIOS settings for HP business class notebooks:

Refer to section 5-Advanced Menu:

PC Commercial BIOS (UEFI) Setup Whitepaper 2018 (919946-003)

To boot from a GPT-formatted disk, you will have to change the settings back again (legacy mode disabled/secure boot enabled).

[itsarinya]

Hi, Paul_Tikkanen
Thank you ever so much for your kind reply.
I selected the "Legacy support enable and Secure Boot disable" option in Security Boot Configuration.
But at startup, I get this message:
A required device is not connected or inaccessible, so the PC doesn't see the MBR-formatted disk.

That means my MBR disque contains Windows is not recognized !

It's very strange that the Minitool Partition application sees 4 partitions on the original disk:
BOOT(FAT32) 499MB / Other 128MB / BitLocker 235GB (100% used) / Recover .4GB.

One question, please.
To reinstall Windows in EUFI, do I have to start from a completely blank (unformatted) GPT disk?

Thank you very much in advance for your help.
Best regards.
Itsarinya

[Paul_Tikkanen]

You're very welcome, Itsarinya.

I'm surprised the notebook didn't see the MBR disk with those settings changed.

To install Windows in UEFI mode, you can leave the disk as is.

Change the BIOS settings back to secure boot enabled, legacy mode disabled.

Boot the Windows installation media from the UEFI USB flash drive.

When you get to the part where you are asked, 'Where do you want to install Windows,' and you get a message that states in substance that 'Windows cannot be installed to this disk. The selected disk has an MBR partition table.'

At that point run the Diskpart utility to clean the disk.

1. Press Shift+F10 from inside Windows Setup screen to open a command prompt window.
2. Type diskpart and press the Enter key.
3. Type list disk to find your disk number.
4. Type select disk (e.g., select disk0) to choose the disk you want to format.
5. Finally, type clean to wipe the disk completely.
6. Exit Diskpart and continue to install Windows.

[itsarinya]

HI, Paul,

You are great ! Thank you so much for your kind advices.

But I don't know what happened to my PC.
When I press the power button, the LED flashes, but the PC won't start!

Do you think that the motherboard is dead ?

Would you  please mind telling me to fix it? 

My deep thanks in advance

Best regards,

Itsrinya

[Paul_Tikkanen]

You're very welcome, Itsarinya.

Unfortunately, I wouldn't know how to fix a problem like that, and I recommended that you start a new discussion on that issue.

Best regards, 

Paul