A management system manages a computer system including multiple monitoring-target devices. A storage device of the management system stores a general rule, general plan information, unresolved information, and configuration information. A control device of the management system creates multiple expanded rules based on the general rule and the configuration information, and if an event related to any of the multiple monitoring-target devices has occurred, identifies, based on the multiple expanded rules, a first conclusion event constituting a candidate for the cause of the occurred event, creates, based on the general plan information, one or more expanded plans, which are recovery plans that can be implemented if the first conclusion event is a cause, identifies an unresolved event based on the unresolved information, identifies a risk site based on the identified unresolved event, and displays data showing the first conclusion event, expanded plan, and risk site.