Dunno if you have seen these errors on an Exchange 2003 server ..
Event ID: 9646
Closing Mapi session “/o=Organization/ou=Administrative Group/cn=Recipients/cn=user” because it exceeded the maximum of 250 objects of type “objMessage”.
Been playing with the figures and couldn’t for the life of me workout if it uses the Hex or Decimal values …. it appears it uses the decimal ;-)