I would like to automate a script that creates an EFI partition.

Currently, one step is manual and requires to start DISKPART and execute these commands:

create partition efi size=100 
format fs=fat32 quick label=SYSTEM 
assign letter=S

How can I get the same result using PowerShell? I haven't seen any option in the New-Partition cmdlet to create an EFI partition.

  • 1
    You should be able to use -GptType '{c12a7328-f81f-11d2-ba4b-00a0c93ec93b}'. If that doesn't work, you can create it as another partition type and use Set-Partition with GptType. – Greg Askew May 26 '18 at 12:58

I suspect this would be the equivalent in PowerShell:

New-Partition -DiskNumber 0 -Size 100MB -GptType "{c12a7328-f81f-11d2-ba4b-00a0c93ec93b}" -DriveLetter "S"
Format-Volume -FileSystem FAT32 -NewFileSystemLabel "SYSTEM" -DriveLetter "S" -Force

Modify as appropriate to suit your use-case.

  • Can you, please, verify it works? I'm getting "Invalid GPT type" errors in for the New-Partition command. Thank you! – SuperJMN May 28 '18 at 8:24
  • Sorry, the GPT type is taken directly from the MSDN docs, you may need to reformat the disk first and make sure it's selecting the right disk? – Adam Parsons May 28 '18 at 8:34
  • I did exactly that. Unfortunately, it refuses to work: Invalid GPT Type. However, the The GUID is OK according to the docs. – SuperJMN May 28 '18 at 8:40
  • Try Initialize-Disk -Number 0 -PartitionStyle GPT and make sure the disk is not Read-only – Adam Parsons May 28 '18 at 8:52
  • 1
    Hahaha oh gosh, I'm sorry. Thanks for updating my answer – Adam Parsons May 31 '18 at 17:17

Please note that you need to select a disk before you can create a partition.

Read diskpart /?, use :

Microsoft DiskPart syntax:
        diskpart [/s <script>] [/?]

        /s <script> - Use a DiskPart script.
        /?          - Show this help screen.

Note that a DiskPart script is simple plain text file where the diskpart commands are placed in (one command per line), for instance MyDiskpart.txt listed below.

diskpart /s MyDiskpart.txt

Answer: The latter command you can run from an elevated powershell session as well as from an elevated cmd session (˙diskpart˙ always requires elevation).


Moreover, Diskpart accepts input from a pipe ('|') as well as from < redirection so that the following cmd commands are equivalent:

diskpart /s MyDiskpart.txt
type MyDiskpart.txt|diskpart

The latter commands tested using the following diskpart script:

==> type MyDiskpart.txt
list disk
list volume
select disk 1
list partition

Moreover, you need not to create a diskpart script file; the following .bat script displays system volume details (selecting volume # dynamically):

SETLOCAL EnableExtensions

echo Administrative permissions required. Detecting permissions...
net session >nul 2>&1
if %errorLevel% == 0 (
    echo Success: Administrative permissions confirmed.
) else (
    echo Failure: Current permissions inadequate.
    goto :endlocal

for /f "tokens=2" %%a in ('echo list volume ^| diskpart ^| findstr System') do (
        echo select volume %%a
        echo detail volume
    ) | diskpart
echo DONE

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