Question Windows 10 will not boot after MBR2GBT /convert command

tycars

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My computer is a HP Elitebook 6930p. The charger shorted 2 weeks ago and I went looking for another. After 5 chargers not working, I figured there was a motherboard issue concluded by some people who own HP laptops. Then I tried to update my BIOS from Legacy to UEFI via Windows command prompt to see if that would solve the problem. Afterwards the computer no longer boots normally and I get Non-System Disk or Disk Error replace and strike.

If I am forced to reinstall windows 10, I’m out of luck because I do not own a disk of windows 10 operating system and my system was probably updated from Vista (my dad gave me this computer few years ago). The only OS disk I own is Windows 7. If I have to reinstall , can I downgrade to 7 and then upgrade to 10 after?

Any help is appreciated.
 

RyzenNoob

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Why not just clean install Windows 10? No need to update from Windows 7

Windows doesn't use GPT as a boot partition, this is the reason why it won't boot, so yes, you've got to re-install Windows 10 from fresh to get it back to MBR

EDIT. Well yes, you can run Windows 10 on a GPT drive, but that has to be set up first before installation. Though, still strangely it isn't standard, and will only run on motherboards with UEFI apparently

Did you have CSM enabled?
 
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USAFRet

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My computer is a HP Elitebook 6930p. The charger shorted 2 weeks ago and I went looking for another. After 5 chargers not working, I figured there was a motherboard issue concluded by some people who own HP laptops. Then I tried to update my BIOS from Legacy to UEFI via Windows command prompt to see if that would solve the problem. Afterwards the computer no longer boots normally and I get Non-System Disk or Disk Error replace and strike.

If I am forced to reinstall windows 10, I’m out of luck because I do not own a disk of windows 10 operating system and my system was probably updated from Vista (my dad gave me this computer few years ago). The only OS disk I own is Windows 7. If I have to reinstall , can I downgrade to 7 and then upgrade to 10 after?

Any help is appreciated.
Was this updated from Win 7 to Win 10?

If so, you do NOT need to go back to 7 and then upgrade again.

Just install Win 10.
Create your own USB to install with.

 
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RyzenNoob

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Or do reply 2 on this site
https://answers.microsoft.com/en-us/windows/forum/windows_10-performance/windows-10-will-not-boot-disk-0-marked-as-gpt/431dbbee-4fdd-4418-8407-98ae9e885bbe

Basically what reply 2 says is to do the following:

Insert your Installation Media and boot from it
Do not Install Windows 10, instead click 'Repair this Computer'
The repair will fail, then click Advanced Options
Open Comnand Prompt and run these commands one at a time:
bootrec /FixMbr
bootrec /FixBoot
bootrec /ScanOs
bootrec /RebuildBcd
Then reboot your System to see if Windows will boot . . .
 
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tycars

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Thanks Everybody.

Unfortunately, I do not have access to another computer and have no choice but to install 7. Why cant I just reverse what I did via command prompt? There’s no way to access command prompt through BIOS?

@USAFRet The computer was upgraded from Vista or Windows 7. Knowing my dad (deceased) probably windows 7.
 

RyzenNoob

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tycars

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The only way I can access command prompt is by putting in an old HD that will not boot past windows but will let me access system recovery options.

I don’t have windows 10 usb. I can’t even make that without access to a computer.
 

tycars

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I’m in disbelief that entering a command via windows has made it impossible for my system to go from UEFI back to legacy. Now I cannot even install windows 7 because it says the disk is of the GPT partition style. I’m shocked that all of this happened because the mbr2gpt command wasnt even successful. God I hate windows.
 

USAFRet

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I’m in disbelief that entering a command via windows has made it impossible for my system to go from UEFI back to legacy. Now I cannot even install windows 7 because it says the disk is of the GPT partition style. I’m shocked that all of this happened because the mbr2gpt command wasnt even successful. God I hate windows.
There are LOTS of things you can do from the commandline to render the system completely inoperable.
And some things are one direction only. Can't go back.

This is but one of the many reasons a good backup routine is necessary.

And this is not unique to Windows. Apple or Linux, you could do the same or worse.
 

tycars

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There are LOTS of things you can do from the commandline to render the system completely inoperable.
And some things are one direction only. Can't go back.

This is but one of the many reasons a good backup routine is necessary.

And this is not unique to Windows. Apple or Linux, you could do the same or worse.
Ok, but what is the solution? Should I buy Windows 10 or some sort of recovery disk?
 

RyzenNoob

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I’m in disbelief that entering a command via windows has made it impossible for my system to go from UEFI back to legacy. Now I cannot even install windows 7 because it says the disk is of the GPT partition style. I’m shocked that all of this happened because the mbr2gpt command wasnt even successful. God I hate windows.
Windows 7 doesn't support GPT, its only for Windows 10 with motherboards that support UEFI, as the link I posted earlier on showed.
 
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How do I create the USB?
Hi tycars.

Here is how you create your own USB Key Windows 10 installation media.
  • Download this on a running system (Windows Media Creation Tool) - https://go.microsoft.com/fwlink/?LinkId=691209
  • Start the tool on the running system.
  • Choose "Create Installation Media".
  • When it ask you where you want to create that media you choose your USB Key (8GB USB Key minimum).
  • The tool will create the media install by itself on your USB Key.
  • When it's over you now have the latest Windows 10 install on that USB Key and you only have to boot to that USB Key to start installing Windows.
 
Windows 7 doesn't support GPT, its only for Windows 10 with motherboards that support UEFI, as the link I posted earlier on showed.
Windows 7 most certainly does support GPT and bootable GPT disks throguh UEFI. Windows Vista was as far as i know, the first consumer Windows version to support bootable GPT disks with a UEFI bios.

I recently had to convert a Windows 7 installation from MBR to GPT, but it was not a simple process. I forgot what software I had started with, but ended up requiring the Windows installer to delete the boot partition and replace it with a new EFI system partition through diskpart. It would have been easier to just wipe partitions and reinstall Windows, but the installation needed to be preserved.
 
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tycars

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Hi tycars.

Here is how you create your own USB Key Windows 10 installation media.
  • Download this on a running system (Windows Media Creation Tool) - https://go.microsoft.com/fwlink/?LinkId=691209
  • Start the tool on the running system.
  • Choose "Create Installation Media".
  • When it ask you where you want to create that media you choose your USB Key (8GB USB Key minimum).
  • The tool will create the media install by itself on your USB Key.
  • When it's over you now have the latest Windows 10 install on that USB Key and you only have to boot to that USB Key to start installing Windows.
Theres no way to buy this USB key?
 

tycars

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Windows 7 most certainly does support GPT and bootable GPT disks throguh UEFI. Windows Vista was as far as i know, the first consumer Windows version to support bootable GPT disks with a UEFI bios.

I recently had to convert a Windows 7 installation from MBR to GPT, but it was not a simple process. I forgot what software I had started with, but ended up requiring the Windows installer to delete the boot partition and replace it with a new EFI system partition through diskpart. It would have been easier to just wipe partitions and reinstall Windows, but the installation needed to be preserved.
All of this and still no solution.
 

tycars

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This command was the culprit: mbr2gpt /convert /allowfullos

I tried another mbr command with an old HD and it caused the disk error as well.
 

tycars

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Hi tycars.

Here is how you create your own USB Key Windows 10 installation media.
  • Download this on a running system (Windows Media Creation Tool) - https://go.microsoft.com/fwlink/?LinkId=691209
  • Start the tool on the running system.
  • Choose "Create Installation Media".
  • When it ask you where you want to create that media you choose your USB Key (8GB USB Key minimum).
  • The tool will create the media install by itself on your USB Key.
  • When it's over you now have the latest Windows 10 install on that USB Key and you only have to boot to that USB Key to start installing Windows.
I created the USB key on a Mac but it’s not booting on the PC.

I downloaded the windows 10 file, then I downloaded a program called Tuxera, and then I used Disk Utility to delete the content on the usb and change it to NFSF and I did the same thing in Tuxera and then I used terminal to copy the files to the usb but my computer isn’t even recognizing it.
 
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