I was having the same issue on Windows 10 Professional system and my unit was not populating on UC. When I loaded the software even though it would detect in Studio One and pull a driver. I had pulled the latest UC V3_4_1_63149 where I had the Issue.
My solution for this was to grab an older version of UC in this case V3_2_0_56558 where support was first listed and the IoStation24C now detects in UC.
I think this may be a similar troubleshooting step for other equipment as well and I encountered the same issue with a fire wire Studio Live 24.4.2 unit on Windows 7 Professional 64bit I had to run some hoops with. Hope this helps people out.