Disable E-mail Address Generation
You can disable automatic e-mail address generation for unnecessary individual address types to reduce network traffic and disk space usage when creating recipients. Disabling automatic generation for a particular address does not remove the address from the recipient policy, but it does prevent it from generating an address for a new recipient.
In Exchange, you must have at least one SMTP and X.400 address type enabled. By default, if an address type has only one address, then that address is the primary address.
To disable e-mail address generation for a recipient policy:
Related TopicsUnderstanding Recipient Policies