Shifting from BIOS to UEFI with the Windows 10 Creators Update MBR2GPT disk conversion tool

Bronze Contributor

Comprehensive yet quick video overview that explains how you can safely and non-destructively convert a Windows 10 machine from legacy BIOS to UEFI disk partitioning; and how you can automate the conversion as part of your in-place upgrade process from Windows 7 to Windows 10.

 

52 Replies
Thank you! This was exactly what I needed to do.

I have been trying to use this converter for a few days now and always get stuck on 

MBR2GPT: Trying to shrink the OS partition

Here is the log:

2018-08-01 12:16:43, Info MBR2GPT was explicitly asked to run in full OS mode.
2018-08-01 12:16:43, Info MBR2GPT: Attempting to convert disk 0
2018-08-01 12:16:43, Info MBR2GPT: Retrieving layout of disk
2018-08-01 12:16:43, Info MBR2GPT: Initial partition information
2018-08-01 12:16:43, Info ===========================================================
2018-08-01 12:16:43, Info Partition layout for disk: 0
2018-08-01 12:16:43, Info Partition style : MBR
2018-08-01 12:16:43, Info MBR signature: 3030528643
2018-08-01 12:16:43, Info Number of partitions : 1
2018-08-01 12:16:43, Info ===================PARTITION===============================
2018-08-01 12:16:43, Info Number: 1
2018-08-01 12:16:43, Info Type: 7
2018-08-01 12:16:43, Info Boot: Yes
2018-08-01 12:16:43, Info Recognized: Yes
2018-08-01 12:16:43, Info Style: 0
2018-08-01 12:16:43, Info Offset: 1048576
2018-08-01 12:16:43, Info Length: 958046142464
2018-08-01 12:16:43, Info Volume: \\?\Volume{b4a23283-0000-0000-0000-100000000000}\
2018-08-01 12:16:43, Info Drive: C:\
2018-08-01 12:16:43, Info NT Path: \Device\HardDisk0\Partition1
2018-08-01 12:16:43, Info ===========================================================
2018-08-01 12:16:43, Info ESP partition size will be 104857600
2018-08-01 12:16:43, Info MBR2GPT: Validating layout, disk sector size is: 512 bytes
2018-08-01 12:16:43, Info BCD: Opening store. Flags: 0x0
2018-08-01 12:16:43, Info BCD: Store path: "\??\GLOBALROOT\device\harddisk0\partition1\Boot\BCD"
2018-08-01 12:16:43, Info BCD: Loaded hive at BCD00000000
2018-08-01 12:16:43, Info BCD: Opening object {9dea862c-5cdd-4e70-acc1-f32b344d4795}
2018-08-01 12:16:43, Info FindOSPartitions: Default boot entry: {6B5EAFC2-954A-11E8-888E-001A7DDA7113}
2018-08-01 12:16:43, Info BCD: Opening object {6b5eafc2-954a-11e8-888e-001a7dda7113}
2018-08-01 12:16:43, Info VERBOSE: Device path: \Device\HarddiskVolume5
2018-08-01 12:16:43, Info VERBOSE: Dos path: \\?\GLOBALROOT\Device\HarddiskVolume5
2018-08-01 12:16:43, Info FindOSPartitions: Volume name for the default boot entry: \\?\Volume{b4a23283-0000-0000-0000-100000000000}\
2018-08-01 12:16:43, Info BCD: BcdGetElementDataWithFlags: Failed to open key.Object: {6b5eafc2-954a-11e8-888e-001a7dda7113} Type: 14000008 Status: c0000034
2018-08-01 12:16:43, Info FindOSPartitions: No Recovery sequence found.
2018-08-01 12:16:43, Info FindOSPartitions: Default boot entry locale: en-us
2018-08-01 12:16:43, Info Bitlocker protection for C:\ is either off or suspended.
2018-08-01 12:16:43, Info Unique ID recap for volumes:
2018-08-01 12:16:43, Info Volume name: \\?\Volume{b4a23283-0000-0000-0000-100000000000}
2018-08-01 12:16:43, Info Unique ID size: 12
2018-08-01 12:16:43, Info MBR2GPT: System partition cannot be removed in full OS mode, leaving it untouched.
2018-08-01 12:16:43, Info MBR2GPT: Trying to shrink the OS partition

 

I have a SanDisk SSD

I noticed that when I try to shrink Volume via Disk management it just hangs on the next window, the Activity Monitor shows a Service Host: Disk Defragmenter / Optimize drives process tat is using 10% CPU, has a growing memory usage as well as about 10MB/s disk usage

 

The exact same thing happens when the MBR2GPT process is "stuck" on Trying to shrink the OS partition
I partitioned the disk using a 3rd party software and create a 2GB Unallocated sector and tried again, same issue.

I also remove the 2 recovery partition on the drive. (I have a USB disk with the windows recovery system)
I am not sure what is going on, but I would really hate to do a complete wipe of the drive and start from scratch.

I welcome any ideas at this point.

I gave it some time and now it failed:

2018-08-01 12:52:50, Info MBR2GPT was explicitly asked to run in full OS mode.
2018-08-01 12:52:50, Info MBR2GPT: Attempting to convert disk 0
2018-08-01 12:52:50, Info MBR2GPT: Retrieving layout of disk
2018-08-01 12:52:50, Info MBR2GPT: Initial partition information
2018-08-01 12:52:50, Info ===========================================================
2018-08-01 12:52:50, Info Partition layout for disk: 0
2018-08-01 12:52:50, Info Partition style : MBR
2018-08-01 12:52:50, Info MBR signature: 3030528643
2018-08-01 12:52:50, Info Number of partitions : 1
2018-08-01 12:52:50, Info ===================PARTITION===============================
2018-08-01 12:52:50, Info Number: 1
2018-08-01 12:52:50, Info Type: 7
2018-08-01 12:52:50, Info Boot: Yes
2018-08-01 12:52:50, Info Recognized: Yes
2018-08-01 12:52:50, Info Style: 0
2018-08-01 12:52:50, Info Offset: 1048576
2018-08-01 12:52:50, Info Length: 957941284864
2018-08-01 12:52:50, Info Volume: \\?\Volume{b4a23283-0000-0000-0000-100000000000}\
2018-08-01 12:52:50, Info Drive: C:\
2018-08-01 12:52:50, Info NT Path: \Device\HardDisk0\Partition1
2018-08-01 12:52:50, Info ===========================================================
2018-08-01 12:52:50, Info ESP partition size will be 104857600
2018-08-01 12:52:50, Info MBR2GPT: Validating layout, disk sector size is: 512 bytes
2018-08-01 12:52:50, Info BCD: Opening store. Flags: 0x0
2018-08-01 12:52:50, Info BCD: Store path: "\??\GLOBALROOT\device\harddisk0\partition1\Boot\BCD"
2018-08-01 12:52:50, Info BCD: Loaded hive at BCD00000000
2018-08-01 12:52:50, Info BCD: Opening object {9dea862c-5cdd-4e70-acc1-f32b344d4795}
2018-08-01 12:52:50, Info FindOSPartitions: Default boot entry: {6B5EAFC2-954A-11E8-888E-001A7DDA7113}
2018-08-01 12:52:50, Info BCD: Opening object {6b5eafc2-954a-11e8-888e-001a7dda7113}
2018-08-01 12:52:50, Info VERBOSE: Device path: \Device\HarddiskVolume5
2018-08-01 12:52:50, Info VERBOSE: Dos path: \\?\GLOBALROOT\Device\HarddiskVolume5
2018-08-01 12:52:50, Info FindOSPartitions: Volume name for the default boot entry: \\?\Volume{b4a23283-0000-0000-0000-100000000000}\
2018-08-01 12:52:50, Info BCD: BcdGetElementDataWithFlags: Failed to open key.Object: {6b5eafc2-954a-11e8-888e-001a7dda7113} Type: 14000008 Status: c0000034
2018-08-01 12:52:50, Info FindOSPartitions: No Recovery sequence found.
2018-08-01 12:52:50, Info FindOSPartitions: Default boot entry locale: en-us
2018-08-01 12:52:50, Info Bitlocker protection for C:\ is either off or suspended.
2018-08-01 12:52:50, Info Unique ID recap for volumes:
2018-08-01 12:52:50, Info Volume name: \\?\Volume{b4a23283-0000-0000-0000-100000000000}
2018-08-01 12:52:50, Info Unique ID size: 12
2018-08-01 12:52:50, Info MBR2GPT: System partition cannot be removed in full OS mode, leaving it untouched.
2018-08-01 12:52:50, Info MBR2GPT: Trying to shrink the OS partition
2018-08-01 13:24:29, Info MBR2GPT: Partition final size is: 957836427264
2018-08-01 13:24:29, Info MBR2GPT: Creating the EFI system partition
2018-08-01 13:24:29, Info Initializing VDS service
2018-08-01 13:24:29, Info Obtaining the VDS disk interface
2018-08-01 13:24:29, Info Retrieving the VDS disk properties
2018-08-01 13:24:29, Error PreparePartition: cannot format partition. Error: 0x00000000, async error: 0x80070057[gle=0x000036b7]
2018-08-01 13:24:29, Error Cannot create EFI system partition. Error: 0x000036B7[gle=0x000036b7]
2018-08-01 13:24:29, Info MBR2GPT: Partition information at error point
2018-08-01 13:24:29, Info ===========================================================
2018-08-01 13:24:29, Info Partition layout for disk: 0
2018-08-01 13:24:29, Info Partition style : MBR
2018-08-01 13:24:29, Info MBR signature: 3030528643
2018-08-01 13:24:29, Info Number of partitions : 1
2018-08-01 13:24:29, Info ===================PARTITION===============================
2018-08-01 13:24:29, Info Number: 1
2018-08-01 13:24:29, Info Type: 7
2018-08-01 13:24:29, Info Boot: Yes
2018-08-01 13:24:29, Info Recognized: Yes
2018-08-01 13:24:29, Info Style: 0
2018-08-01 13:24:29, Info Offset: 1048576
2018-08-01 13:24:29, Info Length: 957836427264
2018-08-01 13:24:29, Info Volume: \\?\Volume{b4a23283-0000-0000-0000-100000000000}\
2018-08-01 13:24:29, Info Drive: C:\
2018-08-01 13:24:29, Info NT Path: \Device\HardDisk0\Partition1
2018-08-01 13:24:29, Info ===========================================================
2018-08-01 13:24:29, Info MBR2GPT-undo: Extending back the OS partition
2018-08-01 13:24:29, Info MBR2GPT: Conversion failed

Do you have the same problem when running MBR2GPT from WinPE? Chances are, you have something running in the full OS that is causing the issue and this is why it is recommended to run MBR2GPT in WinPE.

I was finally able to complete the process.

I did this through the OS, not in PE.

The issue is really with how the process went on my SSD.

It was analyzing it for a while, like a good hour.

But, before the last time I tried it, when it worked, I used the Defragmenter tool to "optimize" my SSD, then it did the same thing, but now it worked. I can post the logs if it is going to help anyone.

I did have a boot problem, my BCD was effed up.

For this I did you WinPE and had to do the assign a letter to the EFI partition, then do the bcdboot c:\windows /s e: command to get the BCD stuff from the installed windows to the EFI partition, now it boots and switched the GPT so all is well.

worked for me like magic !!! deleted one partition using diskpart tool in cmd prompt and voila !! thank u

worked for me like magic !!! deleted one partition using diskpart tool in cmd prompt and voila !! thank u
I Had the same error while trying to convert my mbr hard disk to gpt.
what I did for getting success was the following:
1.- checking my partitions in computer management, I saw my two partitions (system reserved and OS ) were primary partitions, but data partition Or D: (as I use to call it) was in logical partition state.
2.- I installed Minitool Partition Wizard and converted logical partition to primary.
3.- Run into windows Enviroment the mbr2gpt /convert /disk:"number of the disk" /allowFullOS and the... IT WORKED!

Hope you Found this helpful.
I Had the same error while trying to convert my mbr hard disk to gpt.
what I did for getting success was the following:
1.- checking my partitions in computer management, I saw my two partitions (system reserved and OS ) were primary partitions, but data partition Or D: (as I use to call it) was in logical partition state.
2.- I installed Minitool Partition Wizard and converted logical partition to primary.
3.- Run into windows Enviroment the mbr2gpt /convert /disk:"number of the disk" /allowFullOS and the... IT WORKED!

Hope you Found this helpful.

This is happening because you have more than 3 partitions on your disk 0 or disk 1 where you have the windows 10 installed. Or probably you have selected wrong disk. try on disk 0.

Yes! Because that tool is only available for that version and after versions.
Use third party tool to convert the logical partition to primary partition