The message An item was expired by the cache while it was locked (increase your cache timeout) can be accompanied by a spike in CPU usage, gaps in data displayed by the Query Analyzer, or both. The workaround is to edit the apache-tomcat/webapps/ROOT/WEB-INF/classes/com/mysql/etools/monitor/pom/hib/ehcache-mysql.xml file and increase the value for maxElementsInMemory for the cache with the name "com.mysql.etools.monitor.pom.hib.HibInstanceAttribute" so that it is greater than the number of rows in the MySQL Enterprise Monitor inventory_instance_attributes table. This may also require configuring the service manager to have a larger maximum heap size, see Section C.1.1, “Configuring Tomcat Parameters” .