how to convert MBR to GPT?

  1. Posts : 9
    windows 10

    how to convert MBR to GPT?

    I have a problem in installing Windows 10 from usb drive. Error is
    "windows cannot be installed to this disk. the selected disk has MBR partition table. on efi system windows can only installed to GPT disk"

    I have formatted without aware this issue. I have few partition in my hard drive with data.

    I have checked bios . there is no option to disable EFI.

    How can i convert MBR to GTP or Disable UEFI without erase my existing data in other partition.

    Pls advice me

      My Computer

  2. Posts : 18,406
    Windows 11 Pro

    Enable CSM mode in "bios". That is legacy BIOS emulation which should work with MBR partitioning. Since you only have data partition(s) on the drive, you could make a bootable USB of MiniTool Partition Wizard and use that to convert the disk from MBR to GPT. I think the version on Kyhi's Recovery Tools is recent enough to do it:
    Windows 10 Recovery Tools - Bootable Rescue Disk - Windows 10 Forums
      My Computer

  3. Posts : 459
    Windows 8&10

    Just to be clear, an OS will install based on how the install media is booted. Changing some settings in the Bios will allow for one or the other or both. It appears you have booted the install media as UEFI when the drive has been set up as Legacy.

    So my question is, do you want to install as Legacy or UEFI? The install media, if booted correctly, will set the drive configuration as necessary if there are no partitions already on the drive. That is why I, when doing a clean install, will clean the drive with Diskpart during the install. This of course, assumes there is no data you wish to preserve.

    There is a utility to convert an MBR drive to GPT built into the current Win 10 version.
      My Computer

  4. Posts : 4,594
    Windows 10 Pro

    Just choose Legacy mode, I do.

    Use the Boot Menu key (F8) to bring up the boot menu, you should now see 2 options for your usb stick, choose the non UEFI stick.
      My Computers

  5. Posts : 18,406
    Windows 11 Pro

    AddRAM said:
    Just choose Legacy mode, I do.

    Use the Boot Menu key (F8) to bring up the boot menu, you should now see 2 options for your usb stick, choose the non UEFI stick.
    However, in order for the legacy boot option to show up on the (F8) boot menu, CSM mode must be enabled in the firmware settings.
      My Computer

  6. Posts : 4,594
    Windows 10 Pro

    Since the drive already used the MBR boot scheme, where did the drive come from ?

    Was windows installed on this drive in the past on this particular PC ? I only ask because you state it already has data on other partitions, and it`s a MBR drive.

    If so then then CSM should have already been configured to allow a Legacy install and no changes would have to be made to the Bios/UEFI interface ( I still call it the Bios).

    Did you create the USB installer yourself or did you buy it ? If you created it, what program did you use to create the usb installer?

    Saltgrass addressed this point also.
    Last edited by AddRAM; 02 Sep 2017 at 20:41.
      My Computers


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