If you try to run a 32 bit-app in Catalina, Big Sur or an M1 Mac, you’ll get the following “App is not optimized for your Mac and needs to be updated” error message: The latest Apple Silicon M1 chip Macs are also incompatible with 32-bit games or apps and if you’re trying to run 32-bit an M1 Mac, we recommend you skip to the section on 32 bit games and apps on M1 Macs. You can only install 64-bit apps on Big Sur and Catalina which for most people isn’t a problem as almost all major software is now 64-bit. Apple dropped support for 32-bit applications in macOS Catalina and the last macOS to support them was Mojave. Big Sur and M1 Macs do not run 32-bit apps or games.