Cannot create a record in Entity (DMFEntity) D365FO

Building a new custom data entity is one of the many requests you get while working on a D365FO Project.

This happens often when an already data entity is modified. Upon synchronization, the table DMFEntity gets updated with the updated data entity. Meanwhile, the DMFEntity table has the EntityName as a primary Key.

Resolution:

Delete all records in DMFEntity via the SQL Studio.