How To Resize / Recreate GPT EFI System Partition

Windows upgrades may fail if the EFI System Partition (ESP) is too small. This guide explains how to resize or recreate the ESP to meet Microsoft’s latest requirements.

Follow these steps carefully to ensure a smooth upgrade process.

Background

Earlier versions of Windows required a minimum of 100 MB for the ESP. Starting with Windows 11 25H2, Microsoft recommends at least 200 MB, with 260 MB suggested for future-proofing. Systems with only 100 MB ESP may fail to upgrade, showing errors such as 0x800f0922 or 0xc1900104, because the installer cannot update boot files.

Important Notes Before You Begin

• Backup: Always back up your data before making partition changes.
• Layout: This procedure applies to UEFI/GPT systems, not MBR.
• Tools: You will need a third-party partition manager (MiniTool, EaseUS, GParted).
• Media: Windows installation USB is required.

Step 1: Prepare Space with a Partition Manager

Using MiniTool Partition Wizard as an example:

1. Download and install MiniTool Partition Wizard.
2. Shrink the C partition by 100–200 MB from the left side:
   • Right-click C, choose Resize/Move, then drag the left boundary to the right.
   • This creates unallocated space directly before C.
3. If the Microsoft Reserved Partition (MSR, 16 MB) sits between ESP and C, right-click the ESP and extend it into the new unallocated space.
4. Apply changes and reboot.

Step 2: Boot into Windows Setup

If extending isn’t possible, recreate the partitions:

1. Insert the Windows 11 installation USB.
2. Boot into BIOS/UEFI and set boot order to USB.
3. At the Windows Setup screen, press Shift + F10 to open Command Prompt.

Step 3: Recreate ESP and MSR with Diskpart

diskpart
list disk
select disk 0
list partition
select partition 2
delete partition override
select partition 1
delete partition override
create partition efi size=300
format quick fs=fat32 label="ESP"
assign letter=V
create partition msr size=16
list volume
exit

This deletes the old ESP and MSR, then creates a new 300 MB ESP and 16 MB MSR.

NOTE: Replace 0 with your Windows disk number.

Replace 2 with your MSR (16‑megabyte partition number), if needed.

Replace 1 with your ESP (100‑megabyte partition number), if needed.

NOTE: Record your Windows volume and ESP volume letters from the 'list volume' command.

NOTE: If you have an existing partition, you can set the partition ID with:

set id=C12A7328-F81F-11D2-BA4B-00A0C93EC93B

to designate it as an EFI System Partition.

Step 4: Rebuild Boot Files

bcdboot C:\Windows /s V: /f UEFI

Replace C: with your Windows partition letter if different, and V: with your ESP letter.

Final Step

Exit and reboot. Your system should now boot with the new ESP partition successfully.

By resizing or recreating the EFI System Partition, you ensure compatibility with Windows 11 upgrades and avoid common installation errors.

This process future-proofs your system and keeps your boot files stable for upcoming updates.