Installed 10 pro on M.2 SSD, want to boot from this drive only now.

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  1. Posts : 18,433
    Windows 11 Pro

    MiniToolSupport said:
    Win 10 Pro didn't boot after you removed Disk 2 mostly because the system partition of Windows 10 Pro is on disk 2:
    Attachment 214859
    So, you can try Glenstr's method to create an FAT32 EFI partition, then connect Disk 4 only, boot computer from Windows 10 installation disk, and run the command bcdboot N:\windows (replace N with the partition letter of the Windows OS partition) in CMD. It will copy boot file from OS partition and create BCD store to the new EFI partition.
    And that likely will not work unless @Glenstr has his UEFI set to allow booting in CSM mode (or legacy BIOS). His computer is currently booting in UEFI mode as evidenced from the fact that it is an EFI System Partition that it is booting from. Nearly all UEFI computers require a FAT32 partition to boot from in UEFI mode. The Windows OS partition is NTFS - which most UEFI computers will not boot from in UEFI mode. Hence my advice to shrink C: drive partition by 100 MB in order to make room for a FAT32 EFI System Partition. Once a FAT32 partition is established on Disk 4, then the proper command would be
    bcdboot C:\Windows /s N:

    C:\ may need to be changed to whatever drive letter the Windows partition gets in the command prompt and N: would need to be changed to the drive letter assigned to the new FAT32 partition to be used as the EFI system partition.
      My Computer

  2. Posts : 9
    Windows 10 pro
    Thread Starter

    Finally getting around to doing this, I downloaded and installed the partition utility, and shrunk the C drive by 100MB. Then I will either see if the utility will let me copy the boot partition on the original OS disk to the M2 drive, or try the command NavyLCDR suggested.

    One thing I noticed was the partition tool adds a 988MB unallocated space on the opposite end of where I'm placing the 100MB - why is this?

    Also I notice that windows disk manager will let me shrink the C partition by 100MB without adding the unallocated space to the other end - can I just use windows disk manager instead?

    update: I did a test run by shrinking the volume by 100mb in windows disk management, then using Mintool parition wizard to copy the 100MB partition from the original OS disk to the new 100MB of unallocated space on the C drive. It copied okay, assigned the next available drive letter and it shows up as a FAT32 partition now. At this point is it ready to go or do I need to issue that command still?

    I could also format the new unallocated space in windows disk management too, could I not, then issue the command to make it bootable?

    I'll create a recovery bootable DVD before I do any of this, and I'm hoping I can make the C disk bootable without having to boot from recovery media.

    Thanks again everyone for their advice & help.
    Last edited by Glenstr; 09 Feb 2019 at 01:27.
      My Computer


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