CS5 is not officially supported on modern operating systems like Windows 11 or macOS Catalina (10.15) and newer. Users on newer Macs cannot run it because it uses a 32-bit installer. Migrate or download Ps CS 5 Extended to newer iMac
Ensure you have your original installation media. This is typically found on a DVD or via a backup of the installer files downloaded from Adobe’s official archives. adobe photoshop cs5 extended full version install