How do I mount the EFI partition on Windows 8.1 so that it is readable and writeable?

Question

Here is what I do:

1. restart machine with Windows 8.1
2. determine "EFI System" partition with the Disk Management utility
3. run command prompt as administrator
4. type diskpart
5. type select disk 0 then select partition 2 then assign
6. open windows explorer windows+e
7. refresh if the drive is not showing F5
8. try to open drive by double clicking

What I expected to happen:

I can at least look at my EFI partition files.

What happened:

after clicking continue

after clicking "security tab" link, no security tab

What do I need to do to access my EFI partition on Windows 8.1?

Answer 1

One way I found is to open it in the administrator command prompt:

type E: then you can browse around and edit the files

Answer 2

The official way of mounting the EFI partition is

mountvol b: /s

where b: is a drive letter of your choosing. You can remove the mapping with:

mountvol b: /d

You still need to launch explorer.exe with administrative privileges in order to see the mountpoint (kill explorer.exe, then launch one from an elevated command prompt)

Answer 3

The reason why you can't access it on Windows Explorer (File Explorer) is because by default it does not run with administrative privileges. If you let's say kill Explorer and execute it again from an elevated command prompt then you will have access to the EFI partition through File Explorer.

First open an elevated command prompt and give the EFI partition a drive letter, you can do it with mountvol as shown in jmiserez's answer (recommended) or with diskpart. In the following example the EFI partition is on disk 0, partition 1 and will be assigned to letter b:

diskpart
list disk
select disk 0
list partition
select partition 1
assign letter=b
exit

Now kill the File Explorer process and start it with administrative privileges:

taskkill /im explorer.exe /f
explorer.exe

Now you can access the EFI partition with File Explorer.

Note that the EFI partition is a FAT32 file system partition. FAT partitions don't have the Security tab, this is a NTFS feature only.

Answer 4

I tried everything and nothing worked on explorer for me.
I tried killing and running explorer from elevated cmd, and also tried the same with PowerShell and nothing worked.
I could however edit inside cmd and powershell but not GUI/Explorer.

It is very odd but if you Download Explorer++ it works.
Extract it and run as admin

From this post:-

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

Answer 5

Press Start and type gpedit.msc and press Enter This will open your Group Policy Editor.

Expand Administrative Templates

Expand Windows Components -> File Explorer

Locate Remove Security tab in the right pane and double click to open

Select the Disabled radio button and press OK

Now check for your security tab :)

Now, you can add yourself Read/Write permissions or just take the ownership