Quick answer
Boot from Windows installation media, open Command Prompt, and run sfc /scannow, DISM /Online /Cleanup-Image /RestoreHealth, and chkdsk /f C: in that order. If that fails, test your RAM.
What's actually happening here
The error STATUS_IMAGE_CHECKSUM_MISMATCH (0XC0000221) appears during the Windows boot process, usually right after you see the spinning dots or the Windows logo. The message says "The image %hs is possibly corrupt" — that %hs is a placeholder for the actual file name, which often shows as ntoskrnl.exe or winload.exe. What it means is that the boot loader read a critical system file, computed its checksum, and the value didn't match what's stored in the file header. Windows does this deliberately to catch corruption early — it'd rather refuse to boot than run a kernel that's been flipped to garbage.
The usual culprits are, in order of likelihood:
- Failed Windows Update — a partial install left a mismatched driver or system file.
- Disk errors — bad sectors on the system drive, especially if the file got written to a dying area.
- Faulty RAM — a flaky stick can write corrupted data during installation or even during normal use, and the corruption persists.
- Overclocking instability — if you've pushed your CPU or RAM beyond spec, transient errors can corrupt files.
The fix sequence below targets each cause in the order you should try them. Don't skip ahead — the first two steps solve the majority of cases.
Fix steps
Step 1: Boot into Windows Recovery Environment (WinRE)
If you can't get to the desktop, you'll need the Windows installation media. You can create it on another PC using the Media Creation Tool for Windows 10 or Windows 11. Then:
- Insert the USB drive and boot from it.
- Select your language, then click Repair your computer instead of Install.
- Go to Troubleshoot → Advanced options → Command Prompt.
If you have a recovery partition or a system restore point, you might also get to WinRE by force-shutting down three times, but the installation media is more reliable.
Step 2: Run System File Checker and DISM
In the Command Prompt, type these commands one by one, pressing Enter after each:
sfc /scannow
DISM /Online /Cleanup-Image /RestoreHealthsfc checks the integrity of all protected system files and replaces corrupted ones with cached copies. DISM repairs the Windows image itself — it's what fixes the corruption that sfc can't handle. The reason you run DISM after sfc is that DISM needs a healthy image to work from; if the system files are broken, DISM might fail. Run sfc first, then DISM, then sfc again — the second pass often catches what the first missed.
After these, type exit and reboot. If the error persists, move on.
Step 3: Check the disk for errors
Back in the Command Prompt, run:
chkdsk /f C:This scans the file system and marks bad sectors. You might see a message saying the volume is in use and asking to schedule a check — accept it. If you have multiple partitions or drives, run it on each: D:, E:, etc. The /f flag fixes errors, but if the disk has physical damage, chkdsk can only mark the bad areas so Windows avoids them. If you get a report of many unrecoverable errors, that's a sign the drive is dying — back up what you can and replace it.
Step 4: Test your RAM
If the above didn't help, the corruption likely came from bad memory. Download MemTest86 (free version), write it to a USB stick, and boot from it. Let it run for at least one full pass — ideally overnight. Any red errors mean you have faulty RAM. Replace the offending stick. If you're on a prebuilt system, check the warranty.
Note: MemTest86 needs to run outside Windows, so you can't test RAM from within the corrupt OS.
Alternative fixes if the main ones fail
System Restore
In WinRE, go to Troubleshoot → Advanced options → System Restore. Pick a restore point from before the problem started. This won't touch your personal files, but it will undo recent system changes — updates, driver installs, etc. It's a solid fallback if SFC and DISM don't find anything.
Startup Repair
Also in Advanced options, Startup Repair. It's a dumbed-down version of the tools above, but sometimes it fixes boot configuration issues that the manual commands miss. Worth a shot if you're not comfortable with the command line.
Reinstall Windows
If all else fails, you might be looking at a corrupt driver that's not part of the system files. A clean install wipes everything and forces Windows to re-read all files from scratch. Back up your data first — you can do that from WinRE's Command Prompt by copying files to an external drive. It's the nuclear option, but it's effective.
Prevention tip
After you've fixed the issue, do two things. First, run chkdsk /f C: weekly if you suspect disk health issues — you can set it up as a scheduled task, but honestly, just checking the SMART status with CrystalDiskInfo once a month is more useful. Second, if you overclock, stress-test with Prime95 and MemTest86 before trusting the system. Overclocking that's stable in games can still corrupt files under full load — I've seen it happen more than once.
Remember: checksum errors are a safety net, not a punishment. Windows is telling you something's wrong at the hardware level. Ignoring it means you're one corrupted driver away from a bricked system.