If you see pop-ups, banners, redirects, and other material on the screen that is keeping you from accessing normal content, surfing common sites, the PUP is most likely running on the machine. It should be a useful system optimizer with security and AV engine features but adware creators abuse the name and inject PUPs on websites you visit, so revenue can get generated and the shady program installed without your permission. MacKeeper is the program that has not so positive reputation online due to intrusive advertising campaigns and PUPs associated to this name of software. What is MacKeeper pop-up ads? MacKeeper – the program that should provide useful features and improve the performance of macOS devices