The purpose of using the .ACCDE format in Microsoft Access is to create a compiled and locked version of an Access database. This format is used to distribute an application or database to users who do not need to modify the design or objects within the database. By converting an Access database to .ACCDE format, the original source code and design elements are hidden, providing a level of protection against unauthorized access or modifications. This format also improves the performance of the application by optimizing the database objects for execution.Additionally, using .ACCDE format ensures that users cannot accidentally or intentionally make changes to the database structure, data, or code, thereby preserving the integrity and stability of the application.