MBR2GPT error: MBR partition type of Dell OEM partition

I can't really suggest a GUID number to use because it looks like that partition type is a Dell specific and shows as a FAT 16 partition.  I certainly could be wrong but I thought Win 10 could not do FAT 16.

Could you describe the partition as to size and label?  If it was that 40 MB OEM partition, you may not need it.

Hi Saltgrass,

The partition is labeled "OEM partition" in Disk Management and is 102 MB. I have an additional Recovery partition of about 12 GB and the main partition protected with Bitlocker.

My only worry in removing the OEM partition is that I don't know if it has any role in the boot / bitlocker process.

Thanks!

Marco

If I read the info on the MBR2GPT does it say eventually you will have to redo the BitLocker setup?  If so, maybe you could do that now...

If you have a 100 MB partition, it might be a System Reserved partition which had been installed for an earlier OS, but no way for me to know.

If you want to get info on the partition to help make a decision you could use Diskpart to do that.  Open and administrative command prompt to run the commands.  One command is followed by a return and a shorthand for the commands is to use the first three letters so that partition can be par.

The overview of this process is to see what drives you have on your system.  You then select the correct drive and then the correct partition to get the details of that partition.  I will show the process to analyze the EFI system partition on my install.

:\WINDOWS\system32>diskpart Microsoft DiskPart version 10.0.15063.0 Copyright (C) Microsoft Corporation. On computer: TWO-IN-ONE DISKPART> lis dis   Disk ###  Status         Size     Free     Dyn  Gpt   --------  -------------  -------  -------  ---  ---   Disk 0    Online          953 GB  1024 KB        * DISKPART> sel dis 0 Disk 0 is now the selected disk. DISKPART> lis par   Partition ###  Type              Size     Offset   -------------  ----------------  -------  -------   Partition 1    System             200 MB  1024 KB   Partition 2    Reserved            16 MB   201 MB   Partition 3    Primary            473 GB   217 MB   Partition 4    Primary            466 GB   474 GB   Partition 5    Recovery           450 MB   940 GB   Partition 6    Recovery            13 GB   940 GB DISKPART> sel par 1 Partition 1 is now the selected partition. DISKPART> det par Partition 1 Type    : c12a7328-f81f-11d2-ba4b-00a0c93ec93b Hidden  : Yes Required: No Attrib  : 0X8000000000000000 Offset in Bytes: 1048576   Volume ###  Ltr  Label        Fs     Type        Size     Status     Info   ----------  ---  -----------  -----  ----------  -------  ---------  -------- * Volume 2         ESP          FAT32  Partition    200 MB  Healthy    System DISKPART>

No need to redo the Bitlocker setup with mbr2gpt, it is sufficient to temporarily remove the protectors.

Following the steps you detailed for the OEM partition I only get

Partition 1

Type  : DE

Hidden: Yes

Active: No

Offset in Bytes: 32256

which unfortunately does not seem to provide more details than what we knew already. As far as I understand, this is the partition used for Dell diagnostics tool, but I cannot be 100% sure. I wish there was a way to temporarily disable it in the boot sequence to make sure it does not play a critical role.

By the way, I have asked the same question in the comment section of the official documentation article on mbr2gpt, if I learn something there I will update it here too.

Thank you for your help.

You did not get any of the info regarding the listing of formatting type or size?

At one time, there was a situation with a Partition manager which would turn recovery partitions into OEM partitions.  At that time, I believed it only happened with UEFI installs.  Since the Partition type you are seeing is specific to Dell, this situation is probably not in play, but have you ever used EaseUS to configure the partitions on your system?

If you wanted to attach a picture of your Disk Management window, it might help someone see something familiar.  You can do that by using the Rich formatting.  I normally limit the picture size to 250-300 wide.

Have you given any thought to doing a clean install?

Thanks a lot for following up. Compared to factory settings, I have only migrated to a larger disk using clonezilla and enlarged the OS partition. I have also upgraded from Win7 to Win10.

I am attaching a screenshot of my Disk Management window.

Yes, I think a clean install is becoming more and more attractive compared to this.

It looks like you have altered the original configuration which makes it hard to know for sure what you should do.

I know you are booting from the 11 GB partition because it is marked as Active.  So your boot files and probably the BitLocker info is there, but again, I am not familiar with BitLocker operations.  A partition that large normally contains the Recovery image for the original OS.

The 100 MB partition appears to have been the original System Reserved partition, which was an NTFS partition using the normal partition type.  At one time, it contained the Boot files and Recovery tools but now appears to not be used...

Because you cloned from a prior drive, the partition sizes may have been changed or otherwise modified.  So I cannot suggest anything and be certain it would not cause problems for your system.

I don't know how old your system is but since it appears to be UEFI capable, a clean install will, in many cases, improve performance.  

I had the same issue on a Dell E7270. I used the example given and it worked flawlessly for me. For example...

mbr2gpt /convert /disk:0  /map:222={af9b60a0-1431-4f62-bc68-3311714a69ad} /allowFullOS

Hi

Same issue on Dell 3020;

Syntax only worked without the brackets....

mbr2gpt.exe /convert /disk:0  /map:222=af9b60a0-1431-4f62-bc68-3311714a69ad /allowFullOS

When you follow the Microsoft Mechanic Article to see the new GPT disk in diskpart as in https://docs.microsoft.com/en-us/windows/deployment/mbr-to-gpt#logs the disk o is not showing. This can be disconcerting as it says successful then disappears. If the PC is restarted, the same issue comes back and if shutdown, it restarts.

Solution is to restart and hit F12 key and get a one time boot window then to change settings ti UEFI ... all works then.

Peter

I know this is an old thread, but I think that the correct GUID for the Dell partition may be {55691b5a-0000-0000-0000-f08de8000000} , but it has not been tested. This thread comes up on google searches for mbr2gpt problems on Dell machines. Figured I would leave this here for the next person. 

I had success converting it to a Basic Data partition using the details in the response above from @lancorp.

I was upgrading a Windows 7 drive to Win 10, then converting the drive to GPT so I could then replace the drive of a new PC.  (I took the New PC's drive out and used it somewhere else...)

I would think it would work converting it to a basic data partition, however, the GUID I put in is, from what I could gather, the guid for the partition type DE, which is the type of partition the Dell Diagnostics is normally  listed under. But Basic Data would probably work just fine. I was just trying to keep it labed "OEM partition"  

The MSR does not show up.

Your Picture shows a windows 7 MBR legacy partition structure.

Under BIOS/MBR mode: Recovery SYSTEM / WINDOWS

Under UEFI/GPT mode: WINDOWS RE TOOLS / SYSTEM / MSR / WINDOWS

SYSTEM is 100meg with windows 7 install.

It changes to 350 megs  for windows 8

and becomes 550 megs for windows 10 starting with 1809.

The 12 gig Recovery partition is carried forward.

There also used to be small FAT partitions with Diagnostics but those moved into bios .

NEW UEFI Partitions for windows 10 will have 4 partitions

MSR /SYSTEM /RECOVERY /OS

Only 3 will show up in Disk Management.

This is what a tiny 32 gig drive looks like.

Windows 7/8 partition structure

Hi all,

I just went through a few hours of torture converting a Dell Latitude E5570 from MBR to GPT. I had to go to the logs to see why MBR2GPT failed even though the /VALIDATE passed. I had the type 222 partition that the software could not convert, so I used /map:222= but I chose the GUID poorly. Don't use the LDM data partition on dynamic disk that is listed in @lancorp's message! I am not sure if a basic data partition would be any better.

I also learned that using the GUID for dynamic disk data partition caused Disk Manager to show the entire disk as an invalid dynamic disk. Diskpart would not do anything due to the overlapping dynamic partition. I tried manually editing the GUID using a disk editor, with no improvement.

I thought the only way to solve this would be a fresh install of Win10, which I did not look forward to. I finally got it working by deleting the overlapping dynamic partition using a commercial partition manager, and after that I found the 100 MB original partition was still allocated. I also had to go back into the BIOS and fix up the boot order, plus manually add Windows Boot Manager to the list.

Sorry for the long-winded explanation. I guess this proves one should always read to the end of a thread!