Matron Landslide
Mine was repeatable over and over with the different USB cables (they weren't defective, they work fine with other hardware as I noted above) you could use one that works with the keyboard, and everything is fine, then replace it with one of the others, then the issue returns, then replace again with one that works and all is fine again, over and over Ad nauseam.
 
I think it comes down to (as with most things) 'all USB cables aren't created equal'

Thanks again Matron Landslide...

First thing I'm trying tomorrow!

🚀

There is a windows limit on MIDI devices.  If prior devices were installed, even though they are no longer used or ever connected, the limit may have been reached and Windows will not recognize any additional.  I don't remember the limit or how to delete old MIDI devices, but one thing to consider.
 
 

fireberd
There is a windows limit on MIDI devices.  If prior devices were installed, even though they are no longer used or ever connected, the limit may have been reached and Windows will not recognize any additional.  I don't remember the limit or how to delete old MIDI devices, but one thing to consider.
 
 

Not sure if this is still relevant or not
 
https://www.harmonycentra...dows-midi-port-problem

fireberd
There is a windows limit on MIDI devices.  If prior devices were installed, even though they are no longer used or ever connected, the limit may have been reached and Windows will not recognize any additional.  I don't remember the limit or how to delete old MIDI devices, but one thing to consider.

Yep, I haven't had to deal with this for years, but I recall this free utility cleaned up the old USB entries very well:
 
https://www.thewindowsclub.com/usboblivion-remove-usb-traces-windows
 

Thanks Barb and Jon...

I'll check that as well. My client keeps postponing his return session so it's taking a while to try anything