Error Message: STOP: C0000221 Unknown Hard Error or STOP: C0000221 STATUS_IMAGE_CHECKSUM_MISMATCH


The following STOP message appears when a critical system file or other file needed to load Windows is corrupted:

STOP: C0000221 unknown hard error
<path>\<file name>
Alternatively, the error may read as follows:

STOP: 0xC0000221 unknown hard error
c:\winnt\system32\ntdll.dll (or other specific file/driver)
In Windows 2000 the error reads as follows:

<path>\<file name>
This error can appear in many different formats, ranging from a blue system error screen to a dialog box. The type of format depends on how much of the operating system was loaded when the corrupted file was detected.


If you receive this error message, the file listed in the error message is corrupted.


To resolve this issue, you need to either obtain a new copy of the file or reinstall Windows. If reinstallation fails to solve the problem, a hardware or network problem may exist.

More Information

The files that are checked for integrity when Windows starts are:

  • All drivers (except those loaded by the system loader to boot the system)
  • All dynamic link libraries (DLLs), including USER, GDI, SHELL, KERNEL, NTDLL, CRTDLL, etc.
  • All DLLs loaded into the address space of the Windows server (video drivers, printer drivers, etc.)
This error message can be caused when you install an inappropriate driver for your hardware. For example, this error would appear if you installed a MIPS driver on an X86-based computer.


Article ID: 101096 - Last Review: Feb 19, 2007 - Revision: 1