Windows 10: I changed my bios to gpt from legacy mbr in advanced restart using mbr2gpt but then I...

It says "reboot and select proper media or insert boot media in selected boot device and press a key" ive pressed every possible key but I dont know how to boot my windows 10 now

:)

 

what will happen to legacy bios if I convert mbr to gpt?

Hi RaghavVerma2,

I am Dave, I will help you with this.

First check if your BIOS supports UEFI and Secure Boot, do not convert your drive if your BIOS only supports Legacy BIOS.

Then, if your PC supports UEFI, you will need to follow the steps on this link to check if your drive can be successfully converted and use mbr2gpt to try to convert the drive.

https://learn.microsoft.com/en-us/windows/deplo...

Before you try to convert the drive, backup all your personal files to ensure you have a safe cy of your files, in case the conversion goes wrong.

 

MBR to GPT Conversion

This is the Microsoft instructions for conversion MBR2GPT - Windows Deployment | Microsoft Docs you need to understand the process before you start.

I presume you mean enable TPM and it may be that part of secure boot requires the bios to be in UEFI mode and not legacy, before you can change the TPM setting.

Sounds like your system is set in legacy mode and using MBR. To use UEFI the boot disk has to be set to GPT.

Sorry forgot the last bit. The conversion keeps all data in tact.

 

How to convert an MBR disk into a GPT disk

Hi,

Thanks for the reply.

This is an unexpected behavior, after you convert the disk from MBR to GPT, it shouldn’t convert back automatically, however you can try to convert the disk back to GPT format if you are on Windows 10 version 1703 or later using the inbuilt utility
MBR2GPT.EXE.

• Click on Start menu (Windows logo), type
  CMD.
  
• Right click on Command prompt and select
  Run as administrator.
  
• Type MBR2GPT /validate /AllowFullOS
  
• Once the validation is successful, execute the following command and check the results.
  
• Type MBR2GPT /Convert /AllowFullOS
  
• Once the conversion is successful, you must boot the computer into BIOS and change the BIOS mode to
  UEFI.
  

Disclaimer: Modifying BIOS/ complementary metal oxide semiconductor (CMOS) settings incorrectly can cause serious problems that may prevent your computer from booting properly.
Microsoft cannot guarantee that any problems resulting from the configuring of BIOS/CMOS settings can be solved. Modifications of the settings are at your own risk.

For more information about MBR2GPT utility, please refer to the article:
Convert MBR disk into GPT using MBR2GPT.EXE

Hope it helps.

Thanks,

Peer Samie

Microsoft Community-Moderator