Identification of corrupted event data may be provided. Calendar events, such as appointments and meetings, may be created and copied to a plurality of attendee calendars. Changes to the event may be logged and, if the change results from a user interaction with a user interface, a user intent identifier may be associated with the log entry. Other changes that do not result from direct user interaction may not be associated with the user intent identifier. Event corruption detection may identify out-of-sync properties between two calendar events associated with the same meeting and, if the out-of-sync property is not associated with the user intent identifier, the properties may be updated to match each other.