The driver software may not have been properly installed.
Either change the filename (DJM-900SRT_x.xxx.exe) of the driver software’s installer and install again, or check as described below, then reinstall.
1. Disconnect the DJM-900SRT from the computer’s USB port.
Do not connect the DJM-900SRT to the USB port until the driver software has been reinstalled.
2. Uninstall the driver software, then restart the computer.
3. Right-click the driver software’s installer file and open its properties.
4 Click the “Compatibility” tab, then click “Display the settings of all users”.
5. Compatibility mode
Check that “Run this program in the compatibility mode” is not checked.
If it is checked, uncheck it, then click “OK”.