@Izham > Sorry to hear that -- in order to troubleshoot and make sure it's not a problem with the unit itself, please try the following:
- firmware is current
- a different USB cable
- a different port on your computer
- the B port on the DDJ
If none of those problems resolve the issue, you may try another computer, but it may be the hardware. In that case, please contact Pioneer DJ technical support in your region to have your hardware inspected and/or serviced.