After upgrading to Windows 10, I realized that I could no longer access the mounted EFI partition even when explorer is running with admin privileges!!   It took me some time to find a workaround so I thought I share it.   1- Mount the EFI partition to a free mount point: -- Run command prompt as administrator -- Type "mountvol X: /s" (without the quotes, X being an unused mount point)   2- Use Explorer++ (Free, Open Source app) to manipulate the files on the partition: -- -- Run Explorer++ with administrative privileges   Hope you find this useful