I am having trouble accessing the EFI partition on windows 10 I tried this method in cmd (I used Administrative privileges ):

open cmd as admin...

diskpart
sel disk 0
sel part 1 (efi part)
assign letter=b
exit
taskkill /im explorer.exe /f
explorer.exe

But it is not working since windows 10, I used this method fine on 8.1.

this picture shows the error I get when I try to access the partition

enter image description here

  • How is it "not working"? Some errors, or nothing happens after these steps? – gronostaj Sep 1 '15 at 11:03
  • I am able to see the mounted partition but I can't access it. – Raffi CH Sep 1 '15 at 11:04
  • Why are you trying to access the EFI partition exactly? – Ramhound Sep 1 '15 at 11:11
  • @Ramhound because I have multiple operating systems, and should rename a file so I can access the other system. – Raffi CH Sep 1 '15 at 11:13
  • 2
    Interestingly I find that the mounted EFI drive is accessible from the ‘Browse’ button from Task Manager -> ‘Run New Task’ You can then perform basic operations possible with Context Menu (Copy/Paste etc) and even when you run other apps with Admin Privileges e.g. Notepad.exe it can also access the drive from its file menu. The issue seems to be with Explorer. – pat2015 Sep 3 '15 at 8:51

Try the following, which works in Windows 7 and 8, but I can't promise anything with 10:

  1. Open an Administrator Command Prompt window by right-clicking the Command Prompt icon and selecting the option to run it as Administrator.
  2. In the Command Prompt window, type mountvol P: /S. (You can change P: to any unused drive letter; that's arbitrary.)
  3. Use the Command Prompt window to access the P: (EFI System Partition, or ESP) volume.

You'll need to use text-mode commands, rather than the GUI, but this method should work.

Another alternative is to use another OS. Even if you can't boot your other OS now, which you strongly imply, you might be able to use an emergency disk. An Ubuntu installation medium, for instance, should let you access the ESP pretty easily. IIRC, it should show up as a volume in the lower-left corner of the screen; or you can use the standard Linux mount command to mount it in any way you like.

  • 1
    Doesn't work mate – Raffi CH Sep 2 '15 at 23:09
  • 1
    I tried it with a vanilla install of windows 10 1151 64 bit (i.e. not an upgrade from windows 7.). The mounting part worked fine, but the entire directory is read-only! What's the point in that? Well, it worked a bit. Do you know how to make it read-write? – enigmaticPhysicist Nov 21 '15 at 13:56
  • This worked for me in Windows 10, recovery mode. Thanks! – Fredrik Håård Feb 10 '17 at 12:09

Update

in Windows 8.1, Windows 10 and Windows Server starting as of 2012 R2 you can use the following Powershell oneliner for getting Read-Write access to EFI partition:

start ((Get-Partition | ? IsSystem).AccessPaths[0])

Original answer

I have found more straightforward way of getting read/write access to EFI partition from Windows 10:

  1. Open an Administrator Command Prompt window by right-clicking Start button and clicking on Command Prompt (Admin)
  2. In the Command Prompt window, type mountvol, disregard help message in the beginning and notice the list of GUID-based paths of all volumes known to Windows, eg.:

list of volumes' GUIDs

  1. GUID of EFI partition is one of those marked with "NO MOUNT POINT" description - in my case it was the first volume
  2. type start \\?\Volume{.......-....-....-....-...........}\ (of course replace dots with the exact GUID from step #3) and new explorer window will pop up with the contents of EFI partition and read/write access to it - voila!

EFI partition in explorer

  • How do one unmount the volume safely again?, the description on /P sounds destructive? – neslekkiM Jun 7 '17 at 6:38
  • @neslekkiM it is not get mounted, just close explorer – maoizm Jun 29 '17 at 5:39
up vote 8 down vote accepted

The answer is by @pat2015 :

Interestingly I find that the mounted EFI drive is accessible from the ‘Browse’ button from Task Manager -> ‘Run New Task’ You can then perform basic operations possible with Context Menu (Copy/Paste etc) and even when you run other apps with Admin Privileges e.g. Notepad.exe it can also access the drive from its file menu. The issue seems to be with Explorer.

  • Upgraded to Windows 10 Anniversary edition and this permission trouble started. This workaround worked perfectly. I'm guessing doing some kind of "RUNAS" to behave as a SYSTEM user might work as well, but that's no fun. Maybe I'll do that if every other Windows update breaks my bootloader again. – dragon788 Sep 26 '16 at 2:00
  • Windows 10 Creators update fixed this problem. – Muntashir Akon Jun 11 '17 at 14:29
  • 1
    You can also just open the cmd.exe as administrator and use the command line like the good ole dark ages. – user148298 Mar 29 at 15:46

protected by Community Sep 4 '15 at 18:55

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