Windows 10: How to convert a new Hard Drive to GPT During Windows Installation?

Hi guys. I bought a new hard drive a few days ago for a relative of mine, and now I need to install windows OS into that drive. Know this, the drive is new and hasn't been touched yet, so most likely, the drive would show as unallocated. The new drive is 2 TB, and the PC had 500 GB HDD before, so I'll be installing the OS on the new one and format the old one later. From what I know, to use more than 2 TB, the partition format needs to be GPT. I can convert the 500 GB to GPT later. I need to convert the new HDD into GPT during OS installation. I looked around the internet and found some soluti

:)

 

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.

 

Converting a hard drive from GPT to MBR.

Managing disk partitions is a risky task. Make sure you have all your data backed up.

What do you want to do:
- Convert a data drive from GPT to MBR?
- Convert a boot able drive from GPT to MBR?
- Do a clean install using a win 10 installation drive and convert the drive from GPT to MBR?

If it is a data drive you can convert from GPT to MBR.
Diskpart commands will clean up the drive. To convert without loosing data you must use a program like Mini Toll partition wizard .

But if the drive is a boot able drive, you can't just convert from UEFI - GPT to Legacy - MBR. You have to make sure your BIOS can use Legacy boot drive.
You have to boot from an external drive (like WinPE), launch Mini Toll partition wizard, convert from GPT to MBR and rebuild bcdboot.

diskpart
list volume (take note of windows partition letter)
select volume x (replace x with the windows partition letter)
active
exit
bcdboot C:\Windows /s C: /f BIOS
exit

 

Windows 10 installation convert from MBR to GPT without data loss

Hi JKMG72,

Thank you for writing to Microsoft Community Forums.

I'll need a few more details to analyze your concern & provide an accurate solution:

1. Are you still facing the issue with Blue screen?
   
2. Is the D drive a partition created within the same hard disk?
   

The problem might occur if the hard disk is failing. Hard disk can be corrupted because of hardware fault. If we have to convert the disk from MBR to GPT, there is high chance of Data loss. The conversion is possible only if there
are no partitions or volumes present in the disk, which makes it impossible to convert without data loss.

If you wish to recover the data before the conversion, I would suggest you to follow the steps mentioned below.

Method 1: Backup data using Command prompt.

1. Attach the Installation media
   (USB/DVD which has windows 10) into the computer.
   
2. Restart your PC, and then press any key to boot from the USB flash drive or the DVD.
   
3. Click on Repair your computer.
   
4. Select Troubleshoot > Click on Advance options.
   
5. Select Command Prompt from the list.
   
6. Type: Notepad.exe
   
7. This will open the Notepad > Go to File >Select, Open > this will open the Windows explorer window. Attach the External hard disk or backup media to back up your files.
   
8. Click on This PC > Select the C drive (C is the drive, where Windows is installed).
   
9. Open Users folder > Open the Username folder and check if you can find the files or your data.
   
10. Now, right click on the folders > Select Move to and choose the destination as your External Hard Disk.
    
11. You will not see a progress bar, the time depends on the amount of data to be copied. After sometime, plug out the External hard disk, connect it in the different computer and check if you have all the required
    files.
    

Method 2: Convert from MBR to GPT.

Follow the same steps (From 1-5) as above to open the command prompt using Installation media.

1. In the command prompt, type:
   DISKPART
   
2. Then, type: List Disk (Note down the disk which you want to convert to GPT)
   
3. Then, type: Select Disk DiskNumber (Disk number is the disk which is listed in the above command, Ex:
   Select disk 0)
   
4. Now, type: Clean
   
5. Then, type: Convert GPT
   
6. Lastly, type: Exit
   

Now, start the Windows installation to install it in GPT format. If you are facing issues with UNMOUNTABLE_BOOT_DEVICE, I would suggest you to follow the Microsoft article on
Bug Check 0xED: UNMOUNTABLE_BOOT_VOLUME.


Hope it helps.

Let us know if you got the help you needed by clicking ‘Yes’ or ‘No’.

Roohi Taj S

Microsoft Community - Moderator