How to Fix Error 0xc0000221 (Windows Couldn't Load Because a File Is Corrupted)

By ErrorFix · Updated October 23, 2026 · 10 min read

What error 0xc0000221 means

When your PC shows "Your PC needs to be repaired. The operating system couldn't be loaded because the kernel is missing or contains errors" with the code 0xc0000221, Windows has caught a checksum mismatch in one of the files it needs most. Every critical file carries a small fingerprint called a header checksum; Windows compares the stored fingerprint with a freshly computed one at boot, and if they don't match, the file is damaged. Rather than start with broken code — which could scramble your data — Windows halts and shows the error.

The blue screen usually names the offending file. On UEFI systems it is most often \Windows\system32\winload.efi, and the info line reads "The operating system couldn't be loaded because a critical system driver is missing or contains errors." On other systems it may name ntoskrnl.exe, the Windows kernel itself. Microsoft documents this error (KB 4010132) as a file system or file corruption problem. The good news is that the fix is almost always repair, not reinstall — you rebuild or replace the damaged files from the recovery environment, and your documents, photos, and programs come through untouched.

Common causes

• Corrupted file system: file system errors or bad sectors in the system partition damage copies of boot files, which is the most common trigger.
• Interrupted Windows update: a power cut or forced shutdown while files are being written can leave winload.efi or kernel files half-written.
• Bad RAM corrupting files at load time: faulty memory can damage file copies as Windows loads them, causing checksum errors even on a healthy disk.
• Secure Boot or BIOS changes: toggling Secure Boot or switching between UEFI and legacy modes can break signature checks on boot files.
• Failed drive clone or disk imaging: cloning to a new SSD sometimes copies damaged sectors or skips the hidden boot partitions entirely.

How to fix error 0xc0000221 — step by step

Work through these fixes in order. You will need a Windows installation USB — create one on another PC with Microsoft's Media Creation Tool if you don't have one already.

1. Reach the Windows recovery environment. Plug in the Windows installation USB and boot from it — on most PCs, press F12, F9, or Esc during startup to pick the USB drive. Choose your language and keyboard, then click "Repair your computer" instead of Install. If you can't boot from USB, force the recovery screen by interrupting the boot three times in a row: hold the power button when the Windows logo appears, and Windows will enter the recovery environment on the next start.
2. Run Startup Repair first. Go to Troubleshoot, then Advanced options, then Startup Repair. Select your Windows installation and let it run. Startup Repair automatically detects and fixes simple boot record and bootloader problems, and on some systems it resolves 0xc0000221 on its own. If it reports that it couldn't repair the PC, continue to step 3 — the automatic tool only handles simple cases, and the manual fixes below go deeper.
3. Rebuild the boot configuration data with bootrec. From Advanced options, open Command Prompt. Type these commands one at a time, pressing Enter after each: bootrec /scanos to find Windows installations, bootrec /fixmbr to rewrite the master boot record, bootrec /fixboot to write a new boot sector, and bootrec /rebuildbcd to rebuild the boot configuration database. When rebuildbcd asks whether to add the installation to the boot list, type Y and press Enter. Then type exit and restart the PC.
4. Repair the EFI boot files and check Secure Boot. If the error persists, the UEFI boot files need rebuilding. In the recovery Command Prompt, type diskpart, then list vol. Look for the small FAT32 partition labeled as EFI or ESP — usually around 100 MB. Select it with sel vol N (replace N with its number), then type assign letter=X and exit to leave diskpart. Now rebuild the boot files with bcdboot C:\Windows /s X: /f UEFI — replace C: with your actual Windows drive letter if different. If the error still appears, restart into the BIOS (usually Del or F2) and check Secure Boot: if you recently changed it or the boot mode, toggling Secure Boot back to its previous setting can clear signature-based failures.
5. Check the disk and repair system files offline. From the recovery Command Prompt, run chkdsk C: /r on your Windows drive — it takes a while but fixes file system errors and quarantines bad sectors that corrupt boot files. Then run sfc /scannow /offbootdir=C:\ /offwindir=C:\Windows to repair damaged system files offline. Note that drive letters shift in the recovery environment, so confirm yours first with diskpart then list vol and adjust the letters accordingly. If SFC reports it couldn't fix everything, run Dism /Image:C:\ /Cleanup-Image /RestoreHealth from the same prompt, then run SFC again.
6. Test memory and use System Restore or reinstall as a last resort. Go to Troubleshoot, then Advanced options, then System Restore, and choose a restore point from before the error first appeared — restoring earlier healthy boot files often clears 0xc0000221 when repairs don't. If the error keeps returning after every repair, suspect your hardware: run the Windows Memory Diagnostic (search for it once booted, or choose Memory Diagnostic from Advanced options if available) to test your RAM, since bad memory corrupts files during loading. As the final option, perform a clean Windows installation — guaranteed to fix the error, but it erases installed programs, so back up your files first from the recovery Command Prompt if you can.

Did this fix it? Quick checklist

• Windows boots past the blue screen without the 0xc0000221 error
• chkdsk finished with no new bad sectors on the system drive
• SFC /scannow reports "Windows Resource Protection did not find any integrity violations"
• No boot error after two full restarts, including one cold boot

If Windows boots again, don't stop there — back up your important files right away, then open Command Prompt as administrator and schedule a disk check with chkdsk C: /f for the next restart. Error 0xc0000221 is often the first warning of a dying drive or failing memory, so a clean backup now saves you from a bigger failure later. Also create a system image backup (search "Backup settings" in Start) so the next boot failure is a single restore instead of another repair session.