How to get rid of Gray Haze Screen
I use a 2010 Mac mini and recently updated to macOS Sierra (processor speed 2.4 GHz Intel Core 2 Duo, memory 8 GB). When I turn it on and start using it, immediately there is a grayish haze over the entire screen. I've tested the monitor and it is not the monitor. I've started up in safe mode and the haze is gone. Once I'm in safe mode, I restart immediately without pressing any keys during startup, and the haze is back. What is causing this haze? How do I turn it off or get rid of it?
Mac mini, macOS Sierra (10.12.1)