I am running the latest release and I have run into this issue.
I have two profiles and two different configurations. one inch and one metric.
If I close one to open the other I notice the program closes, but the communication to the motion controller is still connected.
I open task manager and scroll down, usually a instance of UCCNC is still running. I have to select it and end task and then the communication to the motion controller will close and I can open the other configuration an all is good. This also happens with the latest test release.
I am running windows 10,motion controllers uc100 and just recently uc400eth. its not a big deal just wanted to let someone know.