Problem solved!
In my case the problem resulted from a string of unfortunate coincidences. In early April I had sent my ASI294MC Pro (3-4 years old) for service. While waiting for the repair I purchased the ASI533MC Pro. Both cameras arrived in the observatory just after the early May Windows 10 update was installed. In the past, I could simply connect the USB3.0 cable to the Win10 laptop and the ASI294MC Pro would power up and connect. Not this time. I then tried the ASI533MC Pro and the experienced the same result. Both were shiny red bricks.
I subsequently suspected hardware or drivers when I discovered the Win10 updates. In fact the Win10 updates were Microsoft's final release of Win10 updates which included device security fixes, etc. I suspected an issue and opened this thread. I then contacted the distributor where I bought both cameras. The sales tech asked which external power supply I was using. I was frankly surprised as the ASI294MC Pro never required external power, however, its service repair included a new mother board. I rechecked the distributor's website and there was no mention of the external power supply requirement for the ASI533MC Pro though it was listed as optional. I ordered the power supply and received it yesterday. Both cameras fired up and connected normally.
I have learned that as of January 2022 the motherboard for the ASI294MC Pro does require external power. I had previously read it was an optional method of powering the cooling fan. I had did not notice the requirement on the ASI533MC Pro. You all may be very well aware of that but if not keep it in mind.
Case closed. Thanks for your help Zzzz!
