Windows 10: Determine whether a usb drive is bootable Solved


  1. Posts : 374
    Windows 10 pro 1803/17134.112
       02 Mar 2018 #1

    Determine whether a usb drive is bootable


    Short of rebooting, is there some way to tell whether a usb drive is bootable?
      My ComputerSystem Spec

  2.    02 Mar 2018 #2

    tcebob said: View Post
    Short of rebooting, is there some way to tell whether a usb drive is bootable?
    Not really. Some cheapie media thumb drives can't be made bootable.

    If a good thumb drive was created with a legit bootable creation tool and has the normal resources on it, (usually 8 items), it should be bootable.

    Click image for larger version. 

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  3. Posts : 7,602
    10 Home x64 (1803) (10 Pro on 2nd pc)
       02 Mar 2018 #3

    To be capable of being made bootable a usb stick has to use an mbr partition table. You may not realise it, but a usb doesn't actually need a partiton table, and many are supplied formatted without one. Such a usb has to be reformatted completely from scratch to give it an mbr in order to make it bootable. This is what the MCT does when it makes a bootable usb, you can also do it yourself with Diskpart.

    Edwin has shown examples of the contents of a typical bootable usb from Microsoft. The folders boot and efi, and the files bootmgr and bootmgr.efi are essentials, the rest may vary depending on the purpose of the usb. A bootable Recovery Drive won't have a setup.exe or autorun.inf, for example.

    In addition, to be bootable on a legacy bios system the partition has to be marked as Active. You can see if it is in Disk Management.
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  4.    02 Mar 2018 #4

    Thanks for reminding me about the MBR stuff, Bree. It had totally slipped my mind that active + MBR is what it takes to be bootable.
    --Ed--
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  5. Posts : 374
    Windows 10 pro 1803/17134.112
    Thread Starter
       02 Mar 2018 #5

    Thanks, all.
      My ComputerSystem Spec


  6. Posts : 7,602
    10 Home x64 (1803) (10 Pro on 2nd pc)
       02 Mar 2018 #6

    EdTittel said: View Post
    Thanks for reminding me ... that active + MBR is what it takes to be bootable.
    Remember, that's only required for a legacy bios system, a uefi system doesn't care if the partition is active or not - if the right files are there it will boot.
      My ComputersSystem Spec

  7.    02 Mar 2018 #7

    Yes, but it explains by it's there on a "generally bootable" UFD, suitable for both BIOS and UEFI platforms. So again: thanks, and thanks one more time for the additional explanation.
    Best wishes,
    --Ed--
      My ComputersSystem Spec


 

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