Windows 10: Converting MBR to GPT for EFI boot?

I've just recently re-installed Windows on my laptop. I had the hard drive set to a GPT format disk since my system supports and previously used UEFI boot, but this install wouldn't allow it so I just went to MBR again..

Is there a way to convert the currently MBR type disk to a GPT format (without losing the current Windows installation) so I can resume using the UEFI format boot? I'd like to later dual boot Linux and I'd pref having a UEFI load over the MBR when that time comes.



Thanks.

:)

 

Windows Installation

On EFI systems, Windows can only be installed to GPT disks. If you use MBR disk, you will receive this error message: Windows cannot be installed to this disk. The selected disk has an MBR partition table. You can convert MBR to GPT and try it again.

 

Windows 10 Creators Update 1703 Crash 88%

I finally nailed this.

Did all the things everyone said, but would still get stuck at 88% and then power off and it reverts back.

The answer................... GPT !!!!!!!!!!

My hard disk was using MBR and BIOS.

Converted the MBR to GPT using a Partition Manager (EASEUS Partition manager).

Straight away the upgrade sails through.

WARNING !!!!

You have to ensure your motherboard can handle EFI/UEFI............ provided your motherboard will support EFI or UEFI then it will work with GPT.

If your motherboard cannot handle EFI/UEFI then if you convert to GPT you will not be able to boot again.

Took me a long time to get to the solution................... but got there in the end. At 88% it is doing data migration, and for some reason it will not work with MBR formatted hard disks.

 

You can Convert MBR to GPT using Diskpart
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.
EaseUS partition master can do it wihout data loss too, you can try it.

 

You can do this and keep all your data. I recently did this on my Windows 10 installation and I followed the procedure described in the youtube clip below. It all went fairly smoothly apart from step 4 where I had to do a deep search in testdisk to identify the partitions that needed to be written.

I would recommend that you study the video a few times to become familiar with each step and also have a hard copy of the steps printed out or at least a second computer nearby that you can refer to if you need to check on what to do next.



I notice that the author has also written a simpler procedure that you can follow here:



Cheers,
Phil

 

Thanks a lot Phil, this is exactly what I needed!

 

How to Convert from MBR to GPT:

• Download and install Macrium Reflect Free and create a backup image of your current MBR Windows 10 to an external HD. (You should anyway before modifying any Windows partitions in case something goes wrong)
• Create a bootable Macrium Rescue disk on a USB/DVD (from Macrium application, click on the first icon on the top left)
• Next, wipe out the disk and install a fresh copy of Windows 10 using GPT partition scheme. The installation should create all the needed partitions and C drive. No need to run updates because you're going to overwrite the C drive with the C drive from the backup.
• Next you'd want to ovewrite the C partition from fresh install with the C partition from the backup image.
  Boot up from the Rescue Image and follow the steps in the video as shown below and you're done.

[youtube]0yorvuMvPGU[/youtube]

 

Topgundcp, I agree your process using Macrium Reflect will be easier and more straightforward but the OP had difficulty doing a fresh install and achieving a GPT partition scheme. At your Step 3 he could run into the same problem again and be no better off.

 

If the OP cannot install Windows using GPT partition scheme then there's something wrong with his settings in the BIOS and/or the selection of which option to boot from. I also thought of his idea is he wants to convert it into GPT without losing any installed applications/data.

Anyway, he needs to fix the problem that he cannot install using GPT first.

 

There's more to getting an EFI boot than just converting it to GPT. You also need to repartition to add the EFI boot partition, and another partition which I can't remember the name of that holds system files.

Try this video Convert Windows 7/8/10 Installation from Legacy to UEFI Without Data Loss (Simpler Method) - YouTube

 

@Mystere
The link you posted was already posted in #4. What I suggested above is simply overwrite the C partition with Macrium and it automatically convert this partition to GPT and Windows will boot up with no problem. Been there, done that.

In addition, the method I used will properly align all partitions as if you do a fresh install without using diskpart to create/convert/format all the needed partitions. Windows is smart enough to re-assign the GUID to point at the C-Drive.

 

Sorry, I missed the first link. But no, converting it to GPT will not make it automatically an EFI boot. There is more to it, yes it may boot up, but won't be EFI.

 

@Mystere
Sorry but did you read the steps I posted ?. What do you mean by: It may boot up, but won't be EFI ? How else does it boot up with a GPT disk ? Here's the screen shot

 

You have an EFI partition. If you were originally an MBR, then it won't have created an EFI. My point is, simply changing to GPT is not enough.

 

What you say is true enough. However, creating the EFI partition is covered in his step number 3.