Windows 10: Windows 10 update converted to GPT, cause boot problems

I just did a fresh install of Windows 10 on an older computer. After a lot of troubleshooting boot issues, I discovered that the drive needs to be formatted as Master Boot Record. This worked fine over multiple reboots.


After installing the latest Windows update, the computer no longer boots. It gets stuck at the black screen with the blue logo. A bit of investigation revealed that the Windows update had converted my disk from MBR to GPT.


Is there a way to block Windows from converting the disk to GPT?

:)

 

Cannot convert GPT to MBR.

Hi Michael,



I suggest you to follow the below steps and check if it helps.

This method you have to backup all your data and delete all partitions and volumes. Then use the
DISKPART command.

• Open command prompt and type in DISKPART and press Enter
• Then type in list disk (Note down the number of disk you want to convert to GPT)
• Then type in select disk number of disk
• Finally type in convert gpt.

Hope the information helps. Do reply if you need further assistance.

 

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

 

Converting MBR to GPT for EFI boot?

Your method did not work for me when converting my current Windows 8 MBR disk, however I did come out knowing how to create Windows PE 5.0 Rescue disk using Macrium after reading your post though.