Mac runs pages of code before starting up
Just bought a used Mac Mini late 2014 3ghz i7. It has no OS installed, so I installed Mojave in the usual manner.
When I start it up, it runs several pages of code then does the normal start up.
Can I fix this? I only have 30 days to return it, so at the least I want to be sure it's not a hardware problem. How can I diagnose this?
Mac mini 2018 or later