I have an original purchase of CS6 but since one of the later MacOS updates I was no longer able to use CS6. I deleted it and downloaded it again. In the folder however, the 'Install' button is not accessible (it's greyed out). When I click on the Install button, a message comes up with:
"Install" needs to be updated. The developer of this app needs to update it to work with this version of macOS. Contact the developer for more information.
Not exactly, you can use CS6 if you can downgrade your OS. If you can't downgrade then you have two options to explore.
Install an older version of OS on an external drive and boot into this drive when you need to use your CS6 applicationYou can investigate using Virtual Machines like VMWare Fusion with the appropriate MAC OS version