Technical Tip: Log description: Device Shutdown

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Description	This article describes the log event under system events in the firewall: 'FortiGate had experienced an unexpected power off!'
Scope	FortiGate.
Solution	Understanding the 'Unexpected Power Outage' Log Message on FortiGate: In FortiGates, this results in a log message indicating an 'unexpected power outage'. This message typically appears under the System Event Logs, specifically within the 'General System Event' category. This log entry is generated when the device detects that it was shut down improperly. It means, not through a graceful power-down or reboot process, but rather due to a sudden loss of power. This is a safety and diagnostic feature that helps administrators track events that may impact device stability or performance.  OR date=2025-05-29 time=05:08:53 eventtime=1748520475614258400 tz="-0700" logid="0100032200" type="event" subtype="system" level="critical" vd="root" logdesc="Device shutdown" msg="Fortigate had experienced an unexpected power off!" Unexpected Power Outage cause. There are several potential reasons why this log might be generated: Power Cable Sabotage or Tampering: If the device’s power cable is intentionally or accidentally disconnected—whether due to physical tampering, human error, or maintenance mishandling—it can result in an abrupt shutdown and trigger this log message. Faulty or Aging Power Cable: Over time, power cables can degrade or become damaged. A worn-out cable may intermittently lose connection, causing power drops that mimic an outage and lead to unexpected shutdowns. Actual Power Outage: The most straightforward cause is a power outage in the facility where the FortiGate device is deployed. If backup power (e.g., UPS systems) fails or is not present, the device loses power suddenly, resulting in this log entry. Best Practices: If this log message is populated: Inspect the physical setup to ensure cables are secure and in good condition. Check the uptime logs to see how often the device is experiencing power losses. Verify the presence and functionality of backup power systems to avoid future abrupt shutdowns. If sabotage or tampering is suspected, review physical security and access controls around the equipment. By investigating the root cause of such messages,  ensure better hardware health, avoid configuration loss, and maintain uninterrupted network operations. There might be a chance of REST API failure after the unexpected power failure, which was observed in v7.4.5, which is resolved in v7.4.7. Related article: Troubleshooting Tip: FortiGate powers off unexpectedly