Systems and methods for synchronizing a device and for ensuring that updates to the device occurring during synchronization are not re-synchronized to the synchronization partner. Generation identifiers (GIDs), which are updated each time a synchronization occurs, are assigned to objects in a store. When synchronization occurs, a sync client uses state information, which is used to indicate which generations have been synchronized, to determine which objects have changed since the last synchronization. The state information includes reserved write GIDs that are only used by a particular sync client that performs writes during a synchronization. Objects having a GID that matches a write GID are not synchronized because they were written by the sync client during the previous synchronization.