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mbr2gpt Cannot find OS Partition? RRS feed

  • Question

  • Hi,

    trying to integrate this step into my in-place TS Win7 to Win10 but it keeps failing with the "Cannot find OS Partition(s) for disk 0". I have read many articles but nobody offered a clear solution for this.

    This is how most of our windows 10 machine's disks look like. So Windows 1903 version, it should convert without problems but TS fails.

    Any suggestions? We need to do this without data loss ofcourse.

    Cheers!

    Wednesday, October 16, 2019 2:00 PM

All replies

  • Hi,

    Have you tried the workaround described the Known issue section of this article? It mentions an issue with win10 v1903 when MBR2GPT.exe runs inside an imaging process such as a System Center Configuration Manager task sequence. And the workaround is to copy the missing files and then commit the change.

    For more details, we may refer to:

    MBR2GPT.EXE

    In addition, is the command line in task sequence is something like this?

    cmd.exe /c mbr2gpt.exe /disk:0 /convert /allowFullOS

    Hope the above information helps.

    Regards,

    Alex Zhu
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    Thursday, October 17, 2019 1:17 AM
  • Hi AlexZhu,

    the command ist exactly like you wrote it, but the workaround - I have not seen this and will try it out during the day and report back.

    Thank you!

    Thursday, October 17, 2019 5:15 AM
  • Hi Tonito,

    It seems there is no update for a couple of days. May we know the current status of the problem? Is there any other assistance we can provide?

    Regards,

    Alex Zhu
    -----------------------------------------------
    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.
    Tuesday, October 22, 2019 8:12 AM
  • Hi Alex,

    no luck with this. I cannot get it to work.

    This is what I get when I do a test run in 1903, and the same (I presume) happens in TS. I apply the step right after the conversion from BIOS to UEFI.

    Is this even meant to be used during the in place TS?

    Thanks

    Tuesday, October 22, 2019 11:03 AM
  • Try it in WinPE like Mike explains here:

    https://miketerrill.net/2017/09/06/windows-10-bios-to-uefi-in-place-upgrade-task-sequence-using-mbr2gpt/

    Ensure that you have a 1903 Boot Image with the additional files mentioned in the Known Issue:

    https://docs.microsoft.com/en-us/windows/deployment/mbr-to-gpt#known-issue

    You can do this over a simple Package in SCCM and copying the files over in WinPE before executing MBR2GPT.

    Tuesday, October 22, 2019 11:32 AM
  • Hi Michael,

    I have the three files in the boot image like described in the ms docs link, I also saw the link and followed it  but it did not work. To me it seems that the mbr2gpt looks only at the 100MB System Reserved partition which is not bootable, but our machines which run Windows 7 are setup this way.

    How can I make mbr2gpt to look at the C: partition?

    Thanks

    Tuesday, October 22, 2019 12:26 PM
  • Hi Tonito,

    Just to confirm with you, have we run mbr2gpt.exe before the firmware conversion or after the conversion. It should before the conversion.

    MBR2GPT.exe can be run from the full OS, or in WinPE, however it should be run before the conversion of BIOS to UEFI during an in-place upgrade and most preferably in WinPE.

    Hope the above information helps.

    Regards,

    Alex Zhu
    -----------------------------------------------
    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.
    Friday, October 25, 2019 1:30 AM
  • Hi Alex,

    I can confirm that I am running the mbr2gpt before firmware conversion and in winpe. The only thing that i will now test is chaning the boot.wim. I had one from before selected. Will report here after it is done.

    Cheers,

    Friday, October 25, 2019 6:17 AM