I searched the entire forum and I could't find one single explanation on what happens internally to the SQL table that stores the appointments, specifically the field 'RecurranceStorage' when a 'recurring exception' occurs. Please provide me with a link that can help me to understand the magic. I want to know how recurrence series keep track of exceptions like 'moving' one instance of the series to another resource or date/time. Your sample code 'ResouceGrouping' has zero code-behind.Thanks in advance.