Install Photoshop CS 6 on Mac Mojave

Apple did not maintain backward compatibility, so try this to install old programs
https://helpx.adobe.com/creative-cloud/kb/install-creative-suite-mac-os-sierra.html

I've run into this issue for CS6. I called up Adobe tech support. They emailed me a link today Jan 3 2020 to download. I suggest doing the same and follow steps below.

1. Once downloaded, open up file and click "Install"

2. If you encounter the same problem as me, you might run into a prompt that prevents you from going further (requiring Adobe Support Advisor- which incidentally doesn't help). 

3. In this case, right-click on "Install" and select Show Package Contents

4. Click on Contents folder that pops up, and open MacOS folder

5. Click Install from here

And that should do the trick!!!

If you encounter problems towards the end of the installation asking you to quit applications running in the background, follow the rest: In may case, it was SafaribookmarksS. You need to Force quit this from Activity Monitor. Do this by going to Finder/Utilities/ActivityMonitor. Select SafaribookmarksS and Force quit. (Do this, by going to the top menu, under View, select Quit Process). Then resume installation process and that should do it! Hope this helps. 

Please be aware that you may run into some issues trying to use CS6 on Mojave. The older the software and the newer the machine, the more problems you'll have. Eventually... you'll want to take a look at the Creative Cloud subscription plans found here. Best of luck!

Presumably your original CS6 serial number was for a Mac version?

If your new Mac doesn't have a disc drive go to kglad links in reply #1 here https://forums.adobe.com/thread/2596028 to download program installers

CS6 and earlier programs HAVE NOT BEEN TESTED AND WILL NOT BE UPDATED for Mac El Capitan or newer operating systems

-which means that you try to use CS6 and earlier at YOUR risk of having problems due to Apple updates

-this is about CS6 (which is from 2012) but it will probably apply to other programs of that age

-Apple did not maintain backward compatibility with old programs in El Capitan or newer operating systems

--Adobe has a workaround to Apple's problem of not maintaining backward compatibility

--READ HERE https://forums.adobe.com/thread/2301916 for an Adobe solution to installing old programs, including a link to installing the old Java runtime that is required