The following error message may occur when monitoring event logs using check-windows-eventlog, Mackerel's official check monitoring plugin.

Because the message resource could not be found, the event log message could not be obtained.
Please access the target server and check the event log directly.

This error occurs when --return is specified in the plugin setting options and no messages exist in the event log detected by the plugin (when the message resource of the service that is outputting the error event log cannot be retrieved because the message file is not registered in the registry).

Please contact the service developer regarding the registration status of the services's message resource.