Not sure if this is the problem here but today it surfaced that a recent update is causing havoc with the software and it's recommended to uninstall, run the cleanup tool, reboot and reinstall.
See the announcement at the top of the main home page: https://community.mcafee.com/community/home/
What happens if you just ignore that prompt or just leave it blank? If it wont continue try running MCPR in Safe Mode.
I tried every possible way to get by and could not. It seems after an install things seem ok, although I'm still tempted to do an uninstall again.
Yes an install will replace the software, so all hopefully will be OK.