Well, I exited the program and the problem persisted.
In Win 10 there is something called 'controlled folder access' that multiple searches had directed me to . . . an ON/OFF setting, but regardless of whether KTS on or exited, a window pops up indicated "IT admin prevents access . . . " and I'm absolutely lost.
In checking KTS logs, the install program was a 'low restriction' and I moved to Trusted. Still no difference.
At this point, waiting on a response from the supplier of this software.