In this chapter, you will explore one of the daunting tasks of Dynamics 365: data migration. The majority of projects that you will undertake will require some level of data migration mainly because your clients will have been working with some legacy system and they will want the legacy data on the new system in order to continue their operations effectively and efficiently. In most cases, the success of the project depends on the data migration. That is, it is only after you migrate the data that you will get to see how the system that you designed and developed is performing. Needless to say, this activity impacts every stakeholder, from the development team to the end users.