Event ID 6008 gets logged to the system event log when a Microsoft system shuts down unexpectedly. You will see the message "The previous system shutdown at time on date was unexpected.
Most often occurs along with a DirtyBootShutdown message.
原因
Unexpected shutdown of system.
対策
For more information, please see https://support.microsoft.com/en-us/topic/event-id-6008-is-unexpectedly-logged-to-the-system-event-log-after-you-shut-down-and-restart-your-computer-2e517ea0-e592-b3ad-d572-501c033f4567