I was having a similar problem using McAfee Multi Access version 126.96.36.199 (3060) on a MacBook Pro OS X El Capitan version 10.11.3. When doing a full manual scan with McAfee I would get the message ”Scanning Stopped. No Response From Scanners”. Restarting the computer and even updating McAfee did not correct the issue. I could not find any information about this issue on the Internet but came upon this post but I couldn't find a resolution. Finally, I zapped PRAM/NVRAM when restarting the computer. Running McAfee and the issue was resolved. To zap PRAM/NVRAM shut the computer down and hold down the following four keys—command (⌘)+option+p+r—simultaneously on startup. Continue to hold down the four keys until you hear a chime and the computer will restart. I then relaunched McAfee and it went through the complete scan without a hitch. I'm posting this in the hopes that anyone having a similar issue will find this useful.