I am having this exact issue. Google led me here, so I am glad I am not alone in this.
When it happens, True Drive shows disconnected and Simucube 2 Pro disappears from devices.
Then, the unit beeps, True Drive shows operational, and Simucube 2 Pro reappears in devices.
Any help is greatly appreciated!
Model: Simucube 2 Pro
Software release: 2021.1
Firmware version: 1.0.33
Servo Drive firmware version: 10826
True Drive version: 1.0.33
Simucube 2 Serial NR: 7014
Drive UID: e186c625
HID UID: 290051-4e535010-2030324e
Version 2OH2 Build 190.42.746
Simucube 2 Pro is in devices
Turn off USB disabled
Using the USB that was included
Power cycle has no effect