In practice, Exchange systems are more frequently migrated than installed anew. In order to migrate to a new version of Exchange Server, it is sometimes necessary to update the operating system to a later version. New versions of operating systems often include requirements regarding the existing domain concept and the existing directory services.

If a migration is not planned and performed carefully, internal communications using Exchange may be disrupted dramatically within the organisation in question, which could subsequently reduce productivity. During migration, configuration problems may occur for reasons such as changes in the configuration settings for the different versions at hand or the options for connecting to directory services. Furthermore, incorrect protocol settings may cause abnormalities related to information transfer, authentication, or encryption.