Convert a Master Boot Record to a GUID Partition Table On Windows

This post is a cry for help for someone who wants to know how they can easily and safely convert a hard disk from a Master Boot Record(MBR) partition to a GUID Partition Table(GPT) partition style without losing data.

There’s a tonne of reasons that make windows users want to convert there religion from MBR style to GPT partition style. But to start with, accept that you’re the one that created the problem to start with.

Some of the problems you might have faced on an MBR disk might be:

• You were unable to create a partition or you have reached maximum partitions allowed to be created in an MBR.
• You want to join the windows 11 squad but the requirements are crying for a GPT partition.
• You cannot use logical partition as boot volume type of issue.

… and so much more. Poor you!

Don’t worry though, I know you’re currently judging me like, :-)

I’m just here to help. Get your machine ready, and let’s get started to convert it to GPT partition style ASAP without losing any data on it.

Converting an MBR partition Style To a GPT Partition Style:

STEP 1: Determine which disk you want to convert to an MBR partition style and delete all its partitions leaving only the partition where the windows operating system is(usually :C drive).

Just deleted the partition which is indicated as unallocated

STEP 2: Open command prompt(CMD) and validate if the disk is eligible for conversion using the below command:

mbr2gpt /validate /disk:0 /allowFullOS

Successful validation shows a disk can now be converted

Fix failed to validate issue by deleting partitions on the drive you want to convert. In my client’s case is disk 0 which is the disk with the primary operating system(windows).

STEP 3: Perform the MBR partition style to GPT partition style conversion with below command:

mbr2gpt /convert /disk:0 /allowFullOS

Conversion has been Completed!

FINAL STEP: Restart your computer and press F2 or the key in your computer responsible for entering into the boot settings and head over to the boot section and change the boot option from LEGACY to UEFI then boot priority and press f10 or the key responsible for making changes and now you’re good to start your computer.

If in feature you ever want to dual boot or something like that and you face a EFI .. has been blocked by the current security policy issue, disable the Secure boot as seen in the image on the left above. Secure boot is a feature that protects the PC boot process by blocking any malicious programs from loading. You can disable it temporary.

Bonus: Cleanup

• If you go to disk management or my PC, you’ll see that system reserved partition is now visible on storage in under MyPC.

• This due to the fact that the partition now has a a drive letter. We can easily fix that by removing the drive letter in it.
• Here’s how:

(i) Right click System Reserved and hit the Remove button then press OK.

(ii) Press Yes on all the prompts that follow:

• After doing that you’re have completed all the steps and cleanups required to have your GPT up, clean and safe.

That’s all! Say Goodbye to MBR issues.