Mac use Cmd-Opt-Control-Shift-, (comma) as a hotkey Is there a way to use CommandOptionControlShift, as  hotkey? 

The same modifier keys (CommandOptionControlShift) work fine with letters, but I can't seem to make it do anything when using the , key. 

Is it a system hotkey that needs to be removed from a plist somewhere? Or is it something deeper that can't be reassigned at all?
Command-Option-Shift-Control-, starts a system diagnose process. I'm not really sure about the specifics, but try it and you'll get a zip archive with some information in it.