I can no longer use certain apps, or reload them, because Yosemite does not recognize power apps, Also, I can no longer use my Epson Scanner to scan negatives into photos. Unfortunately, I also upgraded my laptop to Yosemite, so I am stuck in many ways. I want to get back to the OS version below Yosemite. Yosemite is horrible, even their new formatting is horrible. It takes me back to the days of dos formatting. There is an old saying: "If it isn't broken, don't fix it."