After using 4D's application builder, you may come across a situation where the .4DZ file does not get created and put into the build folder. In this case, check to make sure that the Derived Data folder, Sources folder, and the .4DProject file are contained within the Project folder at the root of the database folder.

According to the 4D Developer website, "a .4dz file is essentially a zipped (packed) version of the project folder", so it is important that the mentioned folders and file remain in the Project folder they are originally designated in.

You can find more information on building 4D applications in the following documentation page: https://developer.4d.com/docs/20/Desktop/building.