Hi MeggsIrishEyes! “I can work with a file, but as soon as I close the window, Photoshop quits as well. Have to keep restarting…”
I had exactly the same problem with CS6 after upgrading to Sierra. I found a workaround. Instead of having “free-floating files” (standard setting) in the main window they have to be “anchored” in their own tab by making sure the following CS6 preference is checked. (At this point I must apologise for the fact that I live in Germany and use CS6 in German, so the 2 enclosed screenshots show CS6 in German, but the layout should be the same in English and I´m sure the necessary checkbox will be in the same place!)
Go to CS6 Preferences, and under what´s probably called “User interface” make sure this box which I think is called “Open documents in Tabs” or similar is checked, quit and restart CS6.
You now get each file or files opened with their own tab, like in, say, Safari!
You can have as many files open at the same time as you like, and closing one or all will no longer crash CS6. I´ve actually found this way of working with files in CS6 to be better, but that´s just my opinion, and I´m not a graphics pro! Hope this helps you out!! Otherwise I´ve found CS6 works fine under Sierra. Cheers, Ian (sorry the screenshots are a bit small)