Recreate a deleted or formatted EFI System Partition on a GPT Windows disk

The Windows disk is GPT and the EFI System Partition (ESP) that held Windows boot files was deleted or formatted. Firmware therefore has no usable Windows Boot Manager files on that disk. If the ESP still exists and only its boot files or firmware entry are missing, do not recreate or format it; use BCDBoot against the existing ESP instead.

Searchable Windows error codes and exact messages

Search the exact firmware message plus the computer/motherboard model. Recovery status codes are not proof of a deleted ESP; the partition table must prove it.

Use this procedure only when all of the following are true:

• The intended Windows disk is GPT.
• The Windows volume is readable and stable.
• No usable ESP exists on that disk, or the existing ESP is present but empty and is handled by the non-destructive branch.
• The target disk is identified by model, capacity, and Windows-volume mapping.
• For a deleted ESP, suitable unallocated space already exists on that exact disk.
• A verified, recoverable full-disk image or equivalent backup exists.

Do not use the create/format branch on MBR, when an ESP already contains other operating-system boot files, when space would have to be created by shrinking or moving partitions, when multiple disks create ambiguity, when the disk is unstable, or when the only problem is a missing NVRAM entry. Do not format an existing ESP merely because Windows does not boot.

The exact Windows build and original ESP size may remain unknown. The disk identity, GPT status, Windows volume, existence and contents of every FAT32 system-looking partition, unallocated-space location, and backup recoverability may not remain unknown.

• Current Windows 10/11 installation media or WinRE
• A verified full-disk image or backup stored elsewhere
• Only the target system disk connected, when practical
• Existing unallocated space on the target disk for the deleted-ESP branch
• AC power and a stable storage device
• A written record or photograph of all DiskPart output before modification

Boot current Windows installation media in UEFI mode and open Repair your computer > Troubleshoot > Advanced options > Command Prompt. Disconnect unrelated internal and external data disks if safe. The correct Windows installation is already identified, but its WinRE letter must still be detected.

1. Record the firmware message and whether Windows Boot Manager is absent.

2. Inspect disks and volumes:

   diskpart
   list disk
   list volume
   

3. Confirm the intended disk has a * in the GPT column. Select it by number and verify identity:

   select disk <Windows-disk-number>
   detail disk
   list partition
   

4. Map the already-identified Windows volume back to this same disk:

   select volume <Windows-volume-number>
   detail volume
   assign letter=W
   

5. Verify Windows:

   exit
   

   dir W:\Windows\System32\Config\SYSTEM
   

6. Return to DiskPart and inspect every small FAT32 partition on every connected disk. Select each candidate and run detail partition and detail volume. An ESP is a GPT partition with the EFI System type, normally FAT32.

7. If a valid ESP exists, assign S:, exit DiskPart, and inspect it:

   dir S:\EFI
   dir S:\EFI\Microsoft\Boot
   

8. Choose the correct branch:

   • ESP exists and contains data: Do not format or recreate it. Preserve the BCD and use Branch A.
   • ESP exists, is the confirmed system partition, remains FAT32, and was emptied or quick-formatted as FAT32: Do not create another partition. Use Branch B.
   • ESP exists but now has the wrong file system or contains ambiguous data: Stop for an imaged, separately reviewed partition-recovery procedure.
   • No ESP exists and verified unallocated space is already present on the target disk: Only then consider Branch C.
   • No ESP and no suitable unallocated space: Stop. This writeup does not shrink or move partitions.

9. Before Branch C, verify the external disk image can be read and that its restore procedure is known. A backup that has never been verified does not satisfy the gate.

Branch A — The ESP exists; only Windows boot files or the firmware entry are missing

1. Assign the existing ESP S:.

2. Preserve its readable BCD:

   md W:\BootRepairBackup\EFI
   copy S:\EFI\Microsoft\Boot\BCD W:\BootRepairBackup\EFI\BCD-before-BCDBoot
   

3. Recreate Windows UEFI boot files without formatting:

   bcdboot W:\Windows /s S: /f UEFI /v
   

4. If the firmware entry alone remains missing, refresh it while preserving boot order:

   bcdboot W:\Windows /p /v
   

5. Restart and test twice.

Branch B — The existing FAT32 ESP was emptied or formatted as FAT32

1. Confirm again that S: is the existing EFI System Partition on the Windows disk, still uses FAT32, and contains no other operating-system boot files that must be restored separately.

2. Do not format it again. BCDBoot can populate the empty FAT32 ESP:

   bcdboot W:\Windows /s S: /f UEFI /v
   

3. Verify the resulting structure:

   dir S:\EFI\Microsoft\Boot
   bcdedit /store S:\EFI\Microsoft\Boot\BCD /enum all /v
   

4. If needed, create or refresh the NVRAM entry:

   bcdboot W:\Windows /p /v
   

5. Restore non-Windows boot files from their own verified backup; BCDBoot restores Windows boot files, not third-party boot managers.

Branch C — The ESP was deleted and suitable unallocated space already exists

This branch creates and formats a new partition. Proceed only after every gate in sections 2 and 7 is satisfied.

1. Re-enter DiskPart and re-identify the target disk by number, GPT marker, model, capacity, and Windows-volume mapping:

   diskpart
   list disk
   select disk <Windows-disk-number>
   detail disk
   list partition
   

2. Confirm that at least 260 MB of suitable unallocated space exists on this exact GPT disk. If it does not, type exit and stop.

3. Create a 260 MB EFI System Partition in that already-unallocated space:

   create partition efi size=260
   

4. Immediately confirm the newly selected partition's type and size:

   detail partition
   

5. Only if it is the newly created 260 MB EFI partition, format that new partition and assign S:

   format quick fs=fat32 label="System"
   assign letter=S
   detail volume
   exit
   

6. Re-verify the offline Windows volume before copying files:

   dir W:\Windows\System32\Config\SYSTEM
   

7. Populate the new ESP:

   bcdboot W:\Windows /s S: /f UEFI /v
   

8. Confirm Boot files successfully created, then inspect:

   dir S:\EFI\Microsoft\Boot
   bcdedit /store S:\EFI\Microsoft\Boot\BCD /enum all /v
   

9. Because using BCDBoot with /s does not itself create a UEFI NVRAM entry, restart and check the firmware boot menu. If Windows Boot Manager is absent, return to WinRE with only the target disk connected and run:

   bcdboot W:\Windows /p /v
   

10. Restart and test twice before reconnecting unrelated disks.

• Existing ESP plus BCDBoot works: The partition was not deleted; only its Windows files or entry needed repair.
• Empty existing ESP is repopulated: Formatting damage was repaired without creating another partition.
• New ESP boots independently: The deleted partition was reconstructed from the verified Windows installation.
• BCDBoot reports a copy failure: Stop. Recheck W:, S:, FAT32 health, free space, and source-file integrity.
• Windows Boot Manager remains absent: Confirm firmware is in UEFI mode and the target disk is the only candidate; then refresh NVRAM without /s.
• Another OS no longer appears: Restore its boot files from its own backup. Windows BCDBoot does not reconstruct them.
• No unallocated space exists: Stop and plan a separately imaged partition-resize procedure.

• Do not format any existing partition unless it is the newly created empty ESP selected in Branch C.
• Do not create a second ESP when a usable one already exists.
• Do not use clean, convert, delete partition, or set id.
• Do not select a disk by number alone; numbers can change between boots.
• Do not shrink or move Windows under this writeup.
• Do not assume a small FAT32 partition is the target ESP without checking its GPT type and disk mapping.
• Do not delete boot files belonging to another operating system.

Branches A and B roll back by restoring the preserved BCD or the verified full-disk image. Branch C changes the partition table and formats a newly created partition; its reliable rollback is restoration of the verified pre-change disk image. Do not attempt to delete the new ESP as an improvised rollback while diagnosing a failed boot.

• Firmware shows Windows Boot Manager for the intended disk.
• The target disk cold-boots twice with unrelated disks disconnected.
• S:\EFI\Microsoft\Boot contains current boot files and a readable BCD.
• The BCD loader points to the intended Windows installation.
• Windows reports the expected GPT system disk and starts after reconnecting data disks.
• The verified pre-change disk image is retained until a new full backup succeeds.

Confidence is high when the partition table proves the ESP absent or empty and BCDBoot reconstructs a working path. Stop if disk identity is ambiguous, GPT is not confirmed, storage is unstable, another ESP may contain required boot files, no verified image exists, unallocated space is absent, or the procedure would require shrinking/moving a partition.