Official comment

If you didn't follow the instructions when installing the drivers, you wouldn't have allowed them to be fully installed, so the device will appear, but not function as expected.
Follow these steps:
- Disconnect the DDJ-1000.
- Download the driver.
- Open the driver package and run the uninstaller file.
- Reboot your computer.
- Open the driver package and run the driver installation file.
- After the installation has completed, give the drivers permission (necessary for High Sierra and Mojave).
- Reboot your computer.
- Connect the DDJ-1000 and test as normal.