iMac Freezes / Bluetooth crashes when unplugging DJM900NXS2

I have a 2015 iMac 27" and I've just connected my Pioneer DJM900NXS2 to the USB, the unit shows us as a soundcard and I'm able to monitor audio on recording programs. When I turn the mixer off or remove the USB cable from the iMac it crashes the system, the bluetooth goes off and the keyboard and mouse no longer work. I have to perform a full shutdown and reboot to get back to a working position.

I read this same problem here but with no final answer to the issue:

https://forums.pioneerdj.com/hc/en-us/community/posts/360038670791-Mac-freezes-when-i-unplug-900nxs2

Hardware Overview:

  Model Name: iMac

  Model Identifier: iMac17,1

  Processor Name: Intel Core i5

  Processor Speed: 3.3 GHz

  Number of Processors: 1

  Total Number of Cores: 4

  L2 Cache (per Core): 256 KB

  L3 Cache: 6 MB

  Memory: 32 GB

  Boot ROM Version: 428.0.0.0.0

  SMC Version (system): 2.34f2

  Serial Number (system): C02QR3ATGG7N

  Hardware UUID: 6C0E99C8-1B48-50A0-BB6C-3974DDC56EE6

Pioneer DJM900NXS2

Running - 2.07 firmware

The USB cable is brand new out the packaging direct to the machine. 

I've also done this but with no different:

1.Uninstall the DJM driver.
2 Execute PRM reset: https://support.apple.com/en-us/HT204063
3.Install the DJM driver

Can anyone help me - this is super frustrating and I see i'm not alone in this issue.