We got rid of the browser hijack pretty quickly - I suggest using Cella's excellent how-to if you ever run into a browser hijack yourself - but the slowdowns were more curious. It was clear to me that his browser had been hijacked. My father-in-law's MacBook Pro had been running into curious slowdowns for a two-year-old laptop and he kept on seeing weird sites taking over his Safari and Firefox search bars. Serenity Caldwell writing for iMore in 2017: The problem: Mac malware in the Library folder There are things you can do without having to burn it all down.
It happens to the best of us (not me, of course).
If your Mac is running slow or you're seeing unusual advertisements within your web browser you might have accidentally installed malware at some point. Though it's not easy to hack into or break through a Mac's security, it is possible, especially if someone accidentally installs malware without realizing it.
