US Patent 7801862 Retention of complex objects

Retention of complex objects is disclosed. An indication is received that retention applied to a root object of a complex object is to be extended to child objects, such as attachments or included files or other content. A snapshot of at least the child objects is stored and the retention that is applied to the root object is extended to the snapshot. Retention of the snapshot ensures that the child objects are retained, so long as and in the same manner as the root object, in the form (e.g., version) in which they are stored at the time retention is applied to the snapshot.