Then I reformatted my main Mac drive, which of course wipes out 100 percent of your content, program, and settings. So I downloaded and installed it on a flash drive. I found out it was easier for me to download the next operating system Mac OS X Mountain Lion 10.8 Then I looked up the operating system that was in use when Photoshop Creative Suite 5 (CS5) came out in 2010. I tried tips and tricks from the Adobe forum to get this working, and the suggestions did not work. The program which debuted in 2010 was not designed to work with it. I could not reinstall Adobe Photoshop CS5 on a Mac with OS X Sierra 10.1.2 So for future browsers and google searchers, here's what I did.
But the tips I was offered in this forum did not work. I was able to reinstall Adobe Photoshop CS5 on a Mac.