My Delightful Challenges with MBR2GPT

The Story

I’m not gonna cover in this blog what MBR2GPT is… honestly there’s mroe than enough coverage on this. Instead mines gonna cover a little rabbit hole I went down. Then how I managed to move on, this might even be a multi part series since I did end up removing my recovery partition in the whole mix up.

How did I get here?

In this case the main reason I got here was due to how I was migrating a particular machine, normally I wouldn’t do it this was but since the old machine was not being reused, I ended up DDing (making a direct coopy) of an SSD from old laptop to M2 SSD on new laptop. New laptop has more storage capacity and since the recovery partition was now smack dab in the center of the disk instead of at the end, I wasn’t able to simply extend the partition within Windows Disk Management Utility (diskmgmt).

Instead I opted to use GParted Live, to move the recovery partition to the end of the drive and extend the usual user data partition containing Windows and all that other fun stuff. Nothing really crazy or exciting here.

After the move and partition expansion ran Windows Check Disk to ensure everything was good (chkdsk /F) and sure enough everything was good. Since this newer laptop uses EUFI and all the fun secureboot jazz along with the Windows 10 OS that was on the SSD already, but the SSD partition scheme was MBR… whommp whomp, but of course I knew about MBR2GPT to make this final transition the easiest thing on earth!

Until….

Disk layout validation failed for disk 0

Ughhhh… ok well I’m sure there’s some simple validation requirements for this script…

  • The disk is currently using MBR
  • There is enough space not occupied by partitions to store the primary and secondary GPTs:
    • 16KB + 2 sectors at the front of the disk
    • 16KB + 1 sector at the end of the disk
  • There are at most 3 primary partitions in the MBR partition table
  • One of the partitions is set as active and is the system partition
  • The disk does not have any extended/logical partition
  • The BCD store on the system partition contains a default OS entry pointing to an OS partition
  • The volume IDs can be retrieved for each volume which has a drive letter assigned
  • All partitions on the disk are of MBR types recognized by Windows or has a mapping specified using the /map command-line option

Ughhh, again, ok that’s a check across the board… wonder what happened…

Well I quickly looked back at my open pages, but couldn’t find it (I must have closed it) but someone on a thread mentioned all they did was delete their recovery partition. I ended up doing this, but it still failed on me…

checking the logs (%windir%/setupact.log)

I had errors, such as partition too close to end, and I extended and shrunk the partition. After going through most random errors in the log I was stuck on one major error I could not find a good solution to…

Cannot find OS partition(s) for disk 0

so I started looking over all the helpful posts on the internet, like this, and this

The first one I came across for general help, and it was a nice post, but it actually didn’t help me solve the problem. The second one I actually hit cause it was literally dead on with my issue…

“After checking logs (%windir%/setuperr.log), it was clear it had a problem with my recovery boot option — it was going through all GUIDs in my BCD (Boot Configuration Data), and failed on the one assigned to recovery entry. This entry was disabled (yet still had GUID assigned to it, which apparently led nowhere and that seems to have been the root cause). I searched some discussion forums, and most of them said that I would have somehow create recovery partition.

Fortunately, it turned out to be a lot easier 🙂 Windows has another command line tool, called REAgentC, which can be used to manage its recovery environment. I ran reagentc /info, which showed that recovery is disabled and its location is not set, but it had assigned the same GUID that was failing when running MBR2GPT. So, I run reagentc /enable, which set recovery location and voila, this time MBR2GPT finished its job successfully.”

That’s cool and all but for me…

  1. I removed my recovery partition, so any GUID pointing to it is irrelevant and its gone
  2. reagentc was not showing as an available command, either on my main Windows installation, or the windows PE that comes with the 1809 installer ISO I was using.

After farting around for a while, finding out I wasted my time with ADK and other annoyance around Windows Deployment methods and solutions when all I wanted was this simple problem solved, I moved on to another solution, a lil more hands on…

If he fixed his with reagentc… and it was due to a problem in the BCD… let’s see what we can do with the BCD directly without third-party tools. Bring on the….. BCDedit!

 

Microsoft Windows [Version 10.0.17763.437]
(c) 2018 Microsoft Corporation. All rights reserved.

C:\WINDOWS\system32>diskmgmt

C:\WINDOWS\system32>mbr2gpt /validate /allowfullos
MBR2GPT: Attempting to validate disk 0
MBR2GPT: Retrieving layout of disk
MBR2GPT: Validating layout, disk sector size is: 512 bytes
Cannot find OS partition(s) for disk 0

C:\WINDOWS\system32>c:\Windows\setuperr.log

C:\WINDOWS\system32>diskmgmt

C:\WINDOWS\system32>mbr2gpt /validate /allowfullos
MBR2GPT: Attempting to validate disk 0
MBR2GPT: Retrieving layout of disk
MBR2GPT: Validating layout, disk sector size is: 512 bytes
Cannot find OS partition(s) for disk 0

C:\WINDOWS\system32>bcdedit

Windows Boot Manager
--------------------
identifier              {bootmgr}
device                  partition=\Device\HarxxiskVolume1
description             Windows Boot Manager
locale                  en-US
inherit                 {globalsettings}
default                 {current}
resumeobject            {c982d23f-8xx8-11e8-b5xx-ed8385ce2xx2}
displayorder            {current}
toolsdisplayorder       {memdiag}
timeout                 30

Windows Boot Loader
-------------------
identifier              {current}
device                  partition=C:
path                    \WINDOWS\system32\winload.exe
description             Windows 10
locale                  en-US
inherit                 {bootloadersettings}
recoverysequence        {b09bfaxx-6xx4-11e9-98ce-ead29f9a0a02}
displaymessageoverride  Recovery
recoveryenabled         No
allowedinmemorysettings 0x15000075
osdevice                partition=C:
systemroot              \WINDOWS
resumeobject            {c982d23f-8xx8-11e8-b5xx-ed8385ce2xx2}
nx                      OptIn
bootmenupolicy          Standard

Even though I disabled the recovery partition via the “recoveryenabled” no setting the issue kept happening, I could only guess it was this setting, but how can I delete it… ohhhhhh

C:\WINDOWS\system32>bcdedit /deletevalue {current} recoverysequence
The operation completed successfully.

C:\WINDOWS\system32>bcdedit

Windows Boot Manager
--------------------
identifier              {bootmgr}
device                  partition=\Device\HarxxiskVolume1
description             Windows Boot Manager
locale                  en-US
inherit                 {globalsettings}
default                 {current}
resumeobject            {c982d23f-8xx8-11e8-b5xx-ed8385ce2xx2}
displayorder            {current}
toolsdisplayorder       {memdiag}
timeout                 30

Windows Boot Loader
-------------------
identifier              {current}
device                  partition=C:
path                    \WINDOWS\system32\winload.exe
description             Windows 10
locale                  en-US
inherit                 {bootloadersettings}
displaymessageoverride  Recovery
recoveryenabled         No
allowedinmemorysettings 0x15000075
osdevice                partition=C:
systemroot              \WINDOWS
resumeobject            {c982d23f-8xx8-11e8-b5xx-ed8385ce2xx2}
nx                      OptIn
bootmenupolicy          Standard

C:\WINDOWS\system32>mbr2gpt /validate /allowfullos
MBR2GPT: Attempting to validate disk 0
MBR2GPT: Retrieving layout of disk
MBR2GPT: Validating layout, disk sector size is: 512 bytes
MBR2GPT: Validation completed successfully

No way! it worked! Secure boot here I come!

I hope this blog posts helps someone else out there!

Summary

Check the logs: C:\Windows\setuperr.log

There might have been a way I could have moved forward without even have deleted my recovery partition, I just happening to know it was not needed for this system, so it was something that was worth a try. However if I probably had looked in the log before even having done that I may have avoided this rabbit hole.

But…. I learnt something, and that was cool.

Note don’t delete your recovery partition. Bringing it back is an extremely painful process without re-install. I will cover how to accomplish this in my next post. I was actually going to this yesterday, however other work has come up. I will however complete the blog post this week… I promise! (It’s like I’m talking to myself in these posts… like no one actually reads these… do they?)

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