Author Topic: My adventure with changing a GPT / UEFI Windows 8 installation to MBR  (Read 8950 times)

Italick

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Hello,

Currently, Diskcryptor does not have a UEFI type of bootloader.  System encryption with Diskcryptor therefore requires MBR based partitioning and boot code.

This post describes how an installation of Windows 8 can be converted from GPT/UEFI to MBR, so that system encryption with Diskcryptor may be possible.  Doing this would carry a significant risk that you lose your data and your operating system.  Making backup images of your drives and storing them on equipment that you are not using to realize the changes is highly advisable.

To test the procedure that I am describing, I reset Windows 8 to the way it was when my PC was new.  It thus had GPT partitioning and the UEFI boot method.

I installed Macrium Reflect Free Edition and Minitool Partition Wizard.  With Minitool Partition Wizard, I shrunk the system partition to about 40 GB.  Then I cloned the internal drive to an external drive with Macrium Reflect.  With Minitool Partition Wizard, I deleted every partition from the clone, except for the Windows system partition.  I used Minitool Partition Wizard to convert the clone from GPT to MBR.  The drive letter of the cloned system partition was F.

I opened an elevated (administrator) command prompt, and entered these commands:

rd /s F:\boot
y
bootsect /nt60 F: /force
bootsect /nt60 F: /force /mbr
bcdboot F:\windows /s F: /f BIOS

I used Minitool Partition Wizard to set the F partition as active on the external drive.

Then, I rebooted to a Macrium Reflect rescue USB drive.  You can make these in Macrium Reflect.  I used Macrium reflect on the rescue USB drive to clone the external hard drive onto the internal hard drive, deleting all former partitions.

I rebooted and changed my BIOS settings to allow legacy (MBR) startup.  On the next boot, it worked.

Then I installed Diskcryptor and encrypted the system.  The encrypted system was bootable after I restarted and entered the password.

Why did I clone the system to an external drive, modify it, and then clone the modified system back to the internal drive?  It is because MiniTool Partition Wizard refuses to change the drive where Windows is running from GPT to MBR.
« Last Edit: February 15, 2015, 04:55:16 am by Italick »

deyab

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Re: My adventure with changing a GPT / UEFI Windows 8 installation to MBR
« Reply #1 on: March 07, 2015, 12:37:39 am »
Italick, I registered for the forum just to say THANK YOU! You the man (woman?)  ;D
Works perfectly on my HP Pavilion

dude

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Re: My adventure with changing a GPT / UEFI Windows 8 installation to MBR
« Reply #2 on: August 02, 2015, 05:42:49 am »
You think you could make a video showing exactly what you did ?

bmorestance

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Re: My adventure with changing a GPT / UEFI Windows 8 installation to MBR
« Reply #3 on: April 27, 2016, 01:33:22 am »
I assume this only works BEFORE  you install and encrypt your drive...
I am stuck with an M.2 SSD encrypted with Windows 10.
Booting gets stuck at Attempting Recovery.
When I tried to decrypt using Hirens Boot CD, no drives are shown to mount.
UGHH

leonard

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Re: My adventure with changing a GPT / UEFI Windows 8 installation to MBR
« Reply #4 on: April 27, 2016, 07:28:24 am »
+1 for Italick!!

I just bought a Dell notebook with Windows 10 and I've been struggling to have it fully encrypted. I've followed this topic with some adaptations and it does work. Removing the original hard drive was not an option for me. It would void my warranty. So I had 2 flash drives: one with a recovery image for Windows and another one with a live Linux (Lubuntu).

I had "Secure Boot" disabled and "Legacy Boot" enabled from the start.

After setting up a fresh install using the recovery image, I booted using the live Linux and used gdisk (apt-get install gdisk) to convert my disk from GPT to MBR and set the C: partition as active/boot. gdisk does all the hard work.

Then I booted using the recovery image and used the command prompt option to run the commands Italick posted.

Quote
rd /s C:\boot
bootsect /nt60 C: /force
bootsect /nt60 C: /force /mbr
bcdboot C:\windows /s C: /f BIOS

After rebooting I got Windows up and running!  ;D
« Last Edit: April 27, 2016, 05:25:44 pm by leonard »

Italick

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Re: My adventure with changing a GPT / UEFI Windows 8 installation to MBR
« Reply #5 on: April 28, 2016, 05:22:38 am »
Quote
... I booted using the live Linux and used gdisk (apt-get install gdisk) to convert my disk from GPT to MBR...

Nice work!  I hinted at the end of my original post that it should be possible, if the right software is used, to convert the C partition from GPT to MBR without a cloning step.  I did not find that software myself.  I try as much as possible to discuss exactly what worked for me when I suggest a technique. 

Minitool tries to protect your computer from your mad decisions.  This results in my workaround of cloning out, and then back in again.  Neither Linux nor Diskcryptor will try to protect you from becoming unable to use your computer.