To ease the transition into Apple Silicon Macs, Apple allows developers to create a Universal Binary, which is an app file that can run on both older Intel and modern Apple Silicon Macs. We’ll explain what they are and how they work.
It’s an App That Runs on Intel and Apple Silicon Macs
In 2020, Apple introduced a new type of Mac that runs on Apple Silicon (with the M1 and M2 chips), which represents a different type of computer architecture than the Intel Macs that came before it. This means Apple Silicon Macs can’t run programs written for Intel Macs without some help.
Apple created two solutions to bridge compatibility between older Intel-based Macs and newer Apple Silicon-based Macs, which began with the M1 chip. The first is Rosetta 2, which is a translation layer that allows Intel apps to run at almost native speed on Apple Silicon Macs. The second is Universal Binary. Universal Binaries are apps that have been compiled to work with both Intel and ARM processors. This means that you can run the same app file on both an Apple Silicon Mac and an Intel Mac.
Note: Universal Binaries aren’t new to Apple Silicon Macs: Apple also used the same branding during its transition between PowerPC and Intel Macs in 2006. And the computer industry tradition of packing binaries for two architectures into one file (called a “fat binary“) goes back much farther than that.
Universal Binaries run natively on Apple Silicon Macs with Apple’s M-series chips, which means they run faster and more efficiently than Intel-only apps that have to be run through Rosetta 2. If we use Apple’s previous architecture transition between PowerPC and Intel as an example, during the first few years of the transition, it’s likely that many apps will be Universal. But as Apple Silicon adoption grows over time, eventually developers will likely shift to producing Apple Silicon-native apps only.
Advantages for Developers
For software developers, Universal Binaries offer a big advantage: They can release a single .APP file that can be used on both types of Macs. This means that there is no need to distribute two separate versions of the same software program.
Developers typically create Universal Binaries by compiling the source code of a software program twice, once for each type of processor. They then combine the resulting executable files into a single Universal Binary (or “Universal 2“) file.
While Universal Binaries offer great advantages, one small downside is that Universal Binaries are typically larger in size than standard executable files. Still, during an architecture transition period, Universal Binaries allow users to run software programs on any type of Mac without having to worry as much about compatibility.
Universal Binary Tips
Now that you know what a Universal Binary is, you might be wondering: Am I using any right now? You can check to see if an app is a Universal Binary by right-clicking the app’s icon in Finder and selecting “Get Info” in the menu that appears. If the app is a Universal Binary, you will see “Application (Universal)” listed in the “Kind” field.
Also, in the “Get Info” window, you can choose if you want to run the Intel version of the app in Rosetta instead of the native Apple Silicon version. To do so, check the box labeled “Open in Rosetta.”
The next time you open the app, the Intel version of the app will run. If you want to go back to running the Apple Silicon-native app later, right-click the app icon, choose “Get Info,” then uncheck “Open Using Rosetta.” Have fun!