How to mount the EFI partition on USB drive from Windows 10.

2019-09-26

Question

_{Thursday, September 26, 2019 8:43 AM}

My Win10 is 1709.
From screenshot, you can see that I created a EFI partition on the USB drive.
But when I ran "assign letter=z" in diskpart command, it failed with the error as following:

DISKPART> list part

  Partition ###  Type              Size     Offset
        
* Partition 1    System             300 MB  1024 KB
  Partition 2    Primary           8000 MB   301 MB
  Partition 3    Unknown             15 GB     8 GB
  Partition 4    Primary             91 GB    23 GB

DISKPART> assign letter=z

Virtual Disk Service error:
The operation is not supported on removable media.

So, my quesiton is how to mount the EFI partition which is on a USB drive?

All replies (2)

_{Friday, September 27, 2019 6:00 AM}

Hi ,

Thanks for your posting here.

I did not find Microsoft official document talking about this behavior.

However, I have seem some similar cases before, the error is the same as your have.

I would suspect that mounting the EFI partition on a USB drive is not supported in windows system.

Best Regards,

Candy

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_{Wednesday, October 2, 2019 1:39 AM}

Hi ,

Just want to confirm the current situations.

Please feel free to let us know if you need further assistance.