“I used to patch 300 NT servers “
And that was back in the days of 64 meg of memory. You had a grasp on what was in the machine.
Imagine now with 64 gig of memory to hide malware and viruses !!
Not if it's running Microsoft Windows, they hide stuff by design.
Didn’t patch that many little over 200 on an average cycle. You always knew something was going to blue screen, just a matter of how many. Things got better when 2012R2 came out, 100 times better with 2016 and 2019...Patches still breaks things as I had a couple recent patches that broke my Domain controllers but was recoverable.