I have a Mac Pro that has an issue I haven't seen with any of my other Macs. Occasionally, once a week or so, the UI will hang and beachball while the rest of the machine will keep running. Skype calls continue, music keeps playing. I can ssh in and use the terminal. Everything works except the UI is completely frozen. I have to power cycle. I'm running the latest macOS, but previous versions did it all well.
Do you I diagnose the root cause of the issue.