Rosetta 2 is the layer that allows a Mac with Apple silicon to run software designed for Intel-based Macs. It runs in the background anytime you use a software that was designed exclusively for Mac computers with an Intel CPU, and it automatically adapts the app for use with Apple hardware the first time you run it.
How to check if Rosetta is installed on your Apple Silicon Mac
Rosetta 2 is not installed as part of a typical macOS installation and must be done individually. On the positive side, you won’t have to go looking for it because macOS will ask you if you want to install it the first time you try to run a program that uses Intel-based capabilities.
Simply double-click an app designed for an Intel-based Mac, then select Install from the pop-up menu that displays.
To let the Rosetta 2 installation to proceed, enter your login and password, and once the installation is complete, Rosetta will be available for any older apps that require it.
The translation process takes place the first time the app is opened, and it may cause the app’s icon to bounce for a few seconds before it begins, but you won’t notice any performance impact after that. In some circumstances, software written for the x86-64 architecture will run quicker in Rosetta than on Intel Macs.