A Microsoft Windows NT utility executed each time the computer reboots. Autochk.exe checks whether any volumes are dirty (for example, if the system was shut down due to a power failure). If autochk.exe finds a dirty volume, it runs chkdsk /f to attempt to repair it.
Note: Large volumes can take a long time for chkdsk to run. You can prevent autochk from checking specific volumes by using the utility chkntfs.exe found on Windows NT Service Pack 2 and later.