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Missing MSR Partition after MBR2GPT conversion

    Question

  • Hi all,

    I need help or advice.

    I`m preparing Task Sequence in SCCM to convert BIOS/HDD from Legacy/MBR to UEFI/GPT using new MBR2GPT tool from ADK 1703.

     

    Everything is working fine, but after successful conversion I can`t find MSR partition on disk. Is this normal behavior? Can work UEFI/GPT for the future correctly without MSR partition?

     

    I can`t find anything about MSR partition on MBR2GPT docs (http://aka.ms/mbr2gpt). On the other side MSDN says about UEFI/GPT this:

    Beginning in Windows 10, the size of the MSR is 16 MB.

    Add an MSR to each GPT drive to help with partition management. The MSR is a reserved partition that does not receive a partition ID. It cannot store user data.

    https://msdn.microsoft.com/en-us/windows/hardware/commercialize/manufacture/desktop/configure-uefigpt-based-hard-drive-partitions

     

    This is standard partition layout for GPT disk with UEFI Enabled:

    Partition ###  Type              Size     Offset

    -------------  ----------------  -------  -------

    Partition 1    System            1008 MB  1024 KB - EFI (ESP)

    Partition 2    Reserved            16 MB  1009 MB - MSR

    Partition 3    Primary            236 GB  1025 MB - Windows

    Partition 4    Recovery           984 MB   237 GB - Recovery

     

    Standard partition layout for MBR disk:

    Partition ###  Type              Size     Offset

    -------------  ----------------  -------  -------

    Partition 1    Primary           1024 MB  1024 KB - System

    Partition 2    Primary            236 GB  1025 MB - Windows

    Partition 3    Recovery           984 MB   237 GB - Recovery

     

    Partitions after conversion with MBR2GPT (MSR is missing):

    Partition ###  Type              Size     Offset

    -------------  ----------------  -------  -------

    Partition 1    System            1024 MB  1024 KB - EFI (ESP)

    Partition 2    Primary            296 GB  1025 MB - Windows

    Partition 3    Recovery           984 MB   297 GB - Recovery

     

    Thanx

    Thursday, April 20, 2017 11:26 AM

All replies

  • Hi Thanx,

    That's by design. Since it's the presented only when using the GPT partition layout.

    If you convert GPT to MBR, MSR partition is deleted.

    And don't worry since there is no meaningful data is stored within the MSR.


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    Friday, April 21, 2017 9:44 AM
    Moderator