I have a 27" iMac and upgraded to El Capitan several weeks ago. Now I get intermittent "Greek" looking characters when entering text and the computer stops responding. I called Apple Support twice and the first time they erased several temporary caches and then di a re-install of El Capitan. Each time the computer ran well for a day or so but then the problem recurred. When I try to reboot the computer it sometimes locks up and won't reboot. One of the techs advising me said Apple feels third party programs from Mac Paw can cause trouble with the Mac OS. I have Clean My Mac, a memory enhancing program and a disk drive enhancing software from Mac Paw. Should I uninstall these programs and if so, how? I've had PC's for my entire life until getting a Mac a few years ago. I also have Parallels installed and can run Windows 10 without any problems.
iMac (Retina 5K, 27-inch, Late 2014), OS X Yosemite (10.10), track pad
