Fix "ntoskrnl.exe Is Missing or Corrupt" on Windows 10/11

The fast answer. On Windows 10/11 this error reads "The operating system couldn't be loaded because the kernel is missing or contains errors" with File: \Windows\system32\ntoskrnl.exe and a status code such as 0xc000000f or 0xc0000221. ntoskrnl.exe is the Windows kernel, but the file is often not actually gone — file-system errors, a damaged boot configuration, an interrupted update, or a failing disk produce the same screen. Boot into Windows Recovery (WinRE), run Startup Repair, and if that fails, check the disk and repair system files offline from Command Prompt (confirm the Windows drive letter first):

chkdsk C: /f /r
sfc /scannow /offbootdir=C:\ /offwindir=C:\Windows

Then reboot. Don't download ntoskrnl.exe from a "DLL site" — it must match your exact Windows build.

Why this happens

File-system or disk errors — bad sectors or damaged NTFS metadata where the kernel file lives, often after a power loss or forced shutdown. Check this first.
Interrupted Windows update — a crash or power cut mid-update can leave system files, including the kernel, damaged.
Corrupted boot configuration (BCD) — the boot entry points at the wrong partition or is damaged, so the loader can't read the kernel even though the file is fine.
Failing SSD or hard drive — read errors in the system area surface as a "missing" kernel.
Unstable hardware or malware — overclocked CPU/RAM settings or malicious software that altered system files.

Step-by-step fix

Step 1 — Unplug external devices and undo recent hardware changes

Remove USB drives, SD cards, and external disks, then power on. If you recently overclocked the CPU or RAM or enabled an XMP memory profile, enter BIOS/UEFI setup and load the default settings. Save, reboot, and test.

Step 2 — Get into Windows Recovery (WinRE)

Force three failed boots (power on, then hold the power button as the Windows logo appears, three times) to open Automatic Repair. If the PC stops at the error screen instead, boot from a Windows 10/11 install USB and choose Next → Repair your computer. Then go to Troubleshoot → Advanced options.

Step 3 — Run Startup Repair, or remove the last update

Choose Startup Repair and let it finish. If the error appeared right after a Windows Update, choose Uninstall Updates → Uninstall latest quality update instead. Both leave your files alone. Reboot and test.

Step 4 — Check the Windows volume for disk errors

Open Advanced options → Command Prompt. Drive letters in WinRE often differ from normal Windows, so run dir C:\Windows (then D:, E:…) to find the Windows volume. Then check it, replacing C: with that letter:

chkdsk C: /f /r

If chkdsk reports bad sectors, treat the drive as failing — copy your data off before going further.

Step 5 — Repair ntoskrnl.exe with offline SFC

System File Checker replaces damaged protected files, including the kernel, from the copy Windows keeps in its component store. Run it against the offline installation:

sfc /scannow /offbootdir=C:\ /offwindir=C:\Windows

Wait for it to reach 100%. If it reports it found and repaired files, reboot and test.

Step 6 — Rebuild the boot configuration

If the files check out, the boot entry is the likely problem. On legacy BIOS machines, run:

bootrec /scanos
bootrec /rebuildbcd

Type Y when it lists your Windows installation. On UEFI machines, rewrite the boot files to the EFI System Partition instead (the small FAT32 volume in list vol):

diskpart
list vol
sel vol <EFI-FAT32-vol#>
assign letter=S:
exit
bcdboot C:\Windows /s S: /f UEFI

Look for "Boot files successfully created," then reboot. On UEFI, bootrec /fixboot often returns "Access is denied" — bcdboot is the right tool there.

Step 7 — Roll back with System Restore, then suspect hardware

Still failing? In Advanced options, choose System Restore and pick a restore point from before the error started; personal files are kept. If the error returns after a successful repair, the drive or RAM is the real fault — run the drive maker's diagnostic and a memory test, and plan a replacement.

Data safety: A "missing" kernel is frequently the first visible sign of a dying drive. If the files on this machine matter and you have no backup, image the drive to a known-good external disk before running chkdsk /r — it reads every sector and can push a failing drive over the edge. In diskpart, select only the EFI volume and never run clean, format, or delete partition for this error. Never run repairs on the only copy of irreplaceable data.

GRAM tip: These repairs run in Windows Recovery, which lives on the broken PC or any Windows install USB. Once the machine boots again, plug in GRAM — a free portable repair toolkit that runs from a USB inside Windows — to check the drive's SMART health, read the event logs and crash history for the shutdown, failed update, or disk errors behind it, and let its AI agent confirm the root cause so the kernel error doesn't come back.

Download GRAM free See AI pricing →

FAQ

Can I fix this without a second working computer?

Usually, yes. WinRE lives on the broken PC itself — three failed boots open Automatic Repair, where Startup Repair, System Restore, and Command Prompt are available. If WinRE won't load, boot any Windows install USB and choose Repair your computer. The repair itself needs no second computer. (GRAM runs inside Windows rather than from boot media — use it once the machine boots to verify disk health and confirm the root cause.)

Can I just download a replacement ntoskrnl.exe?

No. The kernel must match your exact Windows version and update level, and files from download sites can be the wrong build or tampered with. Offline sfc restores the correct copy from Windows' own component store, and the error is often caused by the disk or boot configuration rather than the file.

My crash report blames ntoskrnl.exe — is that the same problem?

No. If Windows boots but blue-screens and a dump viewer lists ntoskrnl.exe, the kernel is usually just where the crash surfaced. The real cause is typically a faulty driver, unstable RAM, or an overclock. That's a crash-dump analysis job, not a boot repair.

Microsoft says pressing keys at startup causes this. Does that apply to me?

Not on Windows 10/11. That Microsoft article covers the older "Windows could not start because the following file is missing or corrupt" message and notes it occurs on Windows versions before Windows 7. On current Windows, follow the repair steps above.