Interesting Marc, I have had a similar issue twice now with my recently acquired older ZWO 120MM usb2 and had to unplug the USB and replug to get it to work again. The USB is a 10m active Lindy cable, so that is not the issue. After reading this thread I did some googling I found these articles. If you go down the page and follow along from Windows Mac, etc you get to FW Update and in there is an exe file noting USB2 Camera update 12/11/2019, nil instructions so I have no idea if this is the update patch? Thoughts?
https://www.cloudynights.com/topic/5...-very-strange/
https://indilib.org/forum/general/21...m.html?start=0