Downloading Design Premium error ""install" is damaged and can’t be opened. You should eject the disk image."

I figured out the issue. I can't delete.

IF Mac El Capitan read below

CS6 and earlier programs have not been tested and will not be updated to run on Mac El Capitan

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

That MAY be a false error message due to Mac El Capitan and OLD programs

This information is a MUST DO to install old programs on Mac El Capitan

-you may not get the same error message, but these are some links that MAY help with old programs

Install CS5 on Mac 10.11 https://forums.adobe.com/thread/2003455 may help (also for other than CS5)

-also a TEMPORARY security change https://forums.adobe.com/thread/2039319

-http://mac-how-to.wonderhowto.com/how-to/open-third-party-apps-from-unidentified-developers-mac-os-x-0158095/

-and more on gatekeeper https://support.apple.com/en-au/HT202491

When I click on the error message, this is the description of the error.