The message [Error: Failed to connect audio!!] is shown, or the virtual deck disappears immediately on the Serato DJ Pro screen.

The installation of the driver software may be incomplete or the connection may be causing a problem.
If you've already installed the driver software, try again with the following procedure:

■ Windows
1. Close Serato DJ Pro and disconnect the DDJ-REV7 from your computer.
2. Open the control panel (or [Start] > [Settings] > [Apps]) and uninstall [DDJ-REV7 Driver].
3. Close the Windows
4. Disconnect other USB devices, USB hubs, etc.
5. Start the Windows
6. Download driver software from [here]
7. Install the driver software again.
　*An error will occur when the license agreement screen is displayed and you try to proceed without clicking "I agree".
8. Connect the DDJ-REV7 to another port without using a USB hub, etc.

If you still have the problem, it may be caused by operating system sound settings, etc.
Remove all other USB devices from your computer.
Follow the instructions on the troubleshooting guide Case 3-1 "Check the default device selected in the [Sound] panel" or Case 6 [here]
*The guide is for rekordbox users, however you can fix the problem in the same manner.

■ Mac
1. Close Serato DJ Pro and disconnect the DDJ-REV7 from your computer.
2. Download the driver software from [here].
3. Double-click [DDJ-REV7 Uninstaller] to uninstall it.
4. Close your Mac and disconnect other USB devices, USB hubs, etc.
5. Start your Mac.
6. Double-click [DDJ-REV7 AudioDriver.pkg] to reinstall it.
7. Connect the DDJ-REV7 to another port without using a USB hub, etc.
8. Follow the instructions in the troubleshooting guide [here].
* Unnecessary for macOS Sierra 10.12 or earlier

If you still have the problem, it may be caused by operating system sound settings, etc.
Remove all other USB devices from the Mac, uninstall the virtual audio device etc, and restart the Mac.