MBR2GPT Not Working (Disk Layout validation failed for disk 1)

Hi there, I keep getting this error when trying to convert my system from MBR to GPT.

I had a system made for me (for work) and the company installed my OS in legacy mode... I have two drives, one 512gb NVME Samsung 960 EVO and one Seagate 1 TB disk drive.

I'm booting into command prompt mode (from advanced recovery options) and running the command mbr2gpt /validate /disk:1 .

I had one partition only and even shrunk it by 3 Gigs (unallocated) just to give the tool space (it worked for other users) however I ran into the same issue even after doing that.

Just another note, the 1tb drive (non os) has a System Reserve Partition of 500mb

Any suggestions?

Can you post a screenshot of disk management using the instructions in this tutorial, please?
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As well as providing us with complete system specifications such as make/model # of computer or motherboard?

It's a custom system, specs below:

Intel 8700k
Gigabyte Auroras Gaming 5 Z370 Motherboard
32 GB Kinston HyperX Ram
Samsung 960 EVO 512 nvme m.2 ssd
1 TB SATA Drive
Gigabyte Auroras Nvidia 1080ti

Your system partition is on your hard drive, not on your SSD. The company that installed your Windows 10 did not know what they were doing. If your only goal is to boot in UEFI mode, you do not need a GPT partitioned drive to do that. Your computer, however, does likely need a FAT32 partition with the proper boot files in it to boot in UEFI mode from. You can create this partition on the SSD by opening a Command Prompt (Admin) or Powershell (Admin) and running the following commands:

diskpart
select disk 1
create partition primary size=100
format fs=fat32 quick
assign letter=t
exit
bcdboot C:\Windows /s T: /f UEFI
exit

In the command prompt, the sequence should look like this:

Code:

Microsoft Windows [Version 10.0.17134.1]
(c) 2018 Microsoft Corporation. All rights reserved.

X:\windows\System32>diskpart

Microsoft DiskPart version 10.0.17134.1

Copyright (C) Microsoft Corporation.
On computer: Win10XPE

DISKPART> select disk 1

Disk 1 is now the selected disk.

DISKPART> create partition primary size=100

DiskPart succeeded in creating the specified partition.

DISKPART> format fs=fat32 quick

  100 percent completed

DiskPart successfully formatted the volume.

DISKPART> assign letter=t

DiskPart successfully assigned the drive letter or mount point.

DISKPART> exit

Leaving DiskPart...

X:\windows\System32>bcdboot C:\Windows /s T: /f UEFI
Boot files successfully created.

X:\windows\System32>exit

Then when you reboot your computer, you should be able to boot from the SSD in UEFI mode. You will likely have to change the UEFI firmware settings to boot in UEFI mode, and possibly change the boot priority to boot from the SSD first. Also, the new FAT32 partition will be created right at the end of the C: drive partition, so if you want to reclaim the empty space at the end of the SSD, you will have to use a program like MiniTool Partition Wizard to move the new FAT32 partition to the end of the drive, then extend the C: drive partition to fill the empty space.

I was so confused, because my SSD was set as the C drive and everything was installing onto it. That makes sense. Its a new machine, so I'll just do a clean install and run through everything again tomorrow. Already created a boot usb drive.

Thanks for the help!

Should have just installed the OS my self...

When you do the clean install, remove either the data or power cable from the hard drive so the Windows installer sees only the SSD. That will ensure all the partitions get made on the SSD and not on the hard drive in error.

Yep already had that in mind, thanks again!

NavyLCDR said:

Your system partition is on your hard drive, not on your SSD. The company that installed your Windows 10 did not know what they were doing. If your only goal is to boot in UEFI mode, you do not need a GPT partitioned drive to do that. Your computer, however, does likely need a FAT32 partition with the proper boot files in it to boot in UEFI mode from. You can create this partition on the SSD by opening a Command Prompt (Admin) or Powershell (Admin) and running the following commands:

diskpart
select disk 1
create partition primary size=100
format fs=fat32 quick
assign letter=t
exit
bcdboot C:\Windows /s T: /f UEFI
exit

In the command prompt, the sequence should look like this:

Code:

Microsoft Windows [Version 10.0.17134.1]
(c) 2018 Microsoft Corporation. All rights reserved.

X:\windows\System32>diskpart

Microsoft DiskPart version 10.0.17134.1

Copyright (C) Microsoft Corporation.
On computer: Win10XPE

DISKPART> select disk 1

Disk 1 is now the selected disk.

DISKPART> create partition primary size=100

DiskPart succeeded in creating the specified partition.

DISKPART> format fs=fat32 quick

  100 percent completed

DiskPart successfully formatted the volume.

DISKPART> assign letter=t

DiskPart successfully assigned the drive letter or mount point.

DISKPART> exit

Leaving DiskPart...

X:\windows\System32>bcdboot C:\Windows /s T: /f UEFI
Boot files successfully created.

X:\windows\System32>exit

Then when you reboot your computer, you should be able to boot from the SSD in UEFI mode. You will likely have to change the UEFI firmware settings to boot in UEFI mode, and possibly change the boot priority to boot from the SSD first. Also, the new FAT32 partition will be created right at the end of the C: drive partition, so if you want to reclaim the empty space at the end of the SSD, you will have to use a program like MiniTool Partition Wizard to move the new FAT32 partition to the end of the drive, then extend the C: drive partition to fill the empty space.

I attempted to do this but I get a message saying:
DISKPART> create partition primary size=100

No usable free extent could be found. It may be that there is insufficient
free space to create a partition at the specified size and offset. Specify
different size and offset values or don't specify either to create the
maximum sized partition. It may be that the disk is partitioned using the MBR disk
partitioning format and the disk contains either 4 primary partitions, (no
more partitions may be created), or 3 primary partitions and one extended
partition, (only logical drives may be created).

Is there a fix to this or any other way to do this?

Welcome to the Forum.
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To start, post an image of Disk Manager. Expand the window and columns so we can read them.
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I have a Alienware 15 R3. Here are the specs:
-Intel 7700HQ
-32GB RAM
-Nvidia GTX 1070
-1TB SATA Drive
-256GB SSD