XYZ Probe Plus with VFDs and other ground-loop inducing components

I've had the sme issue since always, but learnt to live with it. Basically I unplug my VFD whenever I needed to probe (mostly in the middle of jobs, changing bits)... which is cumbersome and feels unstable, because every once in a while my controller crashes when doing this ... until...

I just tried my very same cnc/controller/vfd/probe setup, except this time with my laptop, unplugged from the AC mains and voila!

Time to get a USB optoisolator then.

edit: BTW, and this might help other diagnose the problem. I had another issue, the trackpad of my cnc computer was unstable too. Didn't give it much thought asuming it was just "airborne" EMI from the VFD. Well, I just changed the laptop power supply's cable to an unearthed one, and problem begone. Time to resucitate my intent of having home swithces too!

 

I had the same problem with my XYZ probe using an HP SFF PC. When I switched back to an old Surface Pro 3 it had no problems at all. Picked up a USB in-line isolator and everything has been problem-free ever since.

Thanks to everyone that contributed to this thread, most of all to Peter for putting up with all of us.

 

I have an X32 Blackbox that has similar problems. I have been using it for a few months now and it was all working fine. Now my XYZ Plus probe has the green LEDS on any time the ground wire is touching the spindle. I have disconnected everything from the Blackbox except for the Power plug, the Probe plug and the Computer connection to my laptop. If I disconnect the computer cord then the green LEDS go out. Im believing there might be a short in the Blackbox. I have also completely replaced every wire including the wires from the VFD, all the motor wires, all the limit switch wires and the computer connection wire. I had changed nothing from when it was all working and when it started failing.
Thanks for any help.