Exchange systems are tightly intertwined with the Windows operating system and only cooperate with third-party systems using connectors that enable other systems to retrieve e-mails from Exchange servers using certain protocols (e.g. POP3).

If the connectors are not taken into consideration in the installation or migration of Exchange, they may be incompatible with the migrated version of Exchange. As a consequence, e-mails may be lost or accidentally changed.

Outside the homogeneous Microsoft environment, security settings related to the Exchange system are invalid.

If different sub-systems are administered separately, inconsistencies may occur at any time. Improperly connected third-party systems may also cause data to be lost or the system to be blocked.