I have Windows 7 Pro and CANfox shows in device manager as COM4 but system tray SiE MT_API says 'No Hardware Connected'. CANfox works on another PC.
Thank you for the good suggestions.
I forgot to put my actual fix here, sorry.
Needed to go into Windows Services and start the Sondheim Windows service. Since setting this to Auto have had no problems.
At the same time I cleaned up unused COM ports with drivers against them in case the driver could not handle a COM9 or COM10. Just housekeeping.
Many thanks for providing this avenue for support.