Error codes

0xc0000221

Bad image checksum

What it means

A system file or driver does not match its checksum, which means the file is damaged or the hardware reads it wrong.

Common causes

• A corrupted system file
• Failing RAM or drive
• A bad overclock

How to fix it

1. Boot from a Windows USB stick, open Command Prompt and run sfc /scannow /offbootdir=C:\ /offwindir=C:\Windows.
2. Test the RAM: run Windows Memory Diagnostic (search mdsched) or MemTest86 from a USB stick. Any error means a stick or its speed setting is the problem.
3. Undo any overclock or undervolt, including XMP/EXPO memory profiles, and test at stock settings for a day.
4. Run chkdsk C: /r from the recovery prompt and check the drive's health afterwards.