Win95 Chkdisk fails to run

When one particular Win95 machine shuts down, it often hangs. When rebooting, there is a message saying it cannot run Scandisk. “There was an error running Scandisk, or it was canceled. Run Scandisk for Windows as you may still have errors on your disk(s). Press any key to continue starting Windows.” Ctrl-C to exit to DOS and typing Scandisk works just fine, however, followed by a WIN. I can’t figure out why the automatically invoked Scandisk fails to run.