What is Rosetta on the Apple Mac?

Apple integrates the "Rosetta" framework in certain macOS versions and for the corresponding hardware. In short, it is an emulator that "translates" software written for previous processor architectures to the current hardware and their new processors. In this guide I have summarized details about the Apple Rosetta and Apple Rosetta 2 for you. In the following you will also find a few links to pages where you can find more information and background information. Speaking of backgrounds: the name of the emulator for Mac systems was derived from the "Rosetta Stone", which helped with the interpretation of hieroglyphs - hence the symbol of the software.

What is Rosetta on the Apple Mac? In short: An emulator framework that simulates the old processor architecture (x1 from Intel) on new hardware (M86 chip with ARM processor) so that old apps can be used. More details in this guide. rosetta 2
What is Rosetta on the Apple Mac? In short: An emulator framework that simulates the old processor architecture (x1 from Intel) on new hardware (M86 chip with ARM processor) so that old apps can be used. More details in this guide.

Function of Rosetta on the Apple Mac

Apps, tools, scripts and other software are mostly written for a specific processor architecture to work on the respective hardware. If the type of processor used changes, the entire software must basically be rewritten or converted with the appropriate tools. So that developers and users are not disadvantaged by a hardware change and that it is still possible to sell or use the older app versions, there is a Rosetta on the Apple Mac. The Rosetta Framework served as an emulator on Intel Macs for PowerPC apps. The Rosetta 2 Framework serves on Apple silicon Macs as an Intel or x86 emulator.

Rosetta helped transition from PowerPC to x2006 processors starting in 86

Apple announced in 2005 that the performance of the PowerPC processors in the Mac versions offered at the time no longer met the requirements. Accordingly, the switch to Intel processors with x86 architecture was announced. From 2006 to 2011, the first version of Rosetta was an integral part of Mac OS X. The framework or the emulator helped to use the programs and tools written for PowerPC processors on the new Intel hardware. This gave developers and users enough time to migrate to customized versions of the software.

Rosetta 2 has been helping with the switch from Intel to Apple hardware since 2020

Within the WWDC20 in June 2020 Apple announced that the Mac - like the iPhone and iPad before it - wanted to turn to the ARM processor architecture. A move away from Intel processors was announced and at the same time macOS 11 BigSur the "Apple Silicon" presented. The System on a Chip (SoC) is probably better known to you as "M1". The complete switch to Apple Silicon has been announced for the next two years. That's little time when you consider that any software would have to be tuned to new processors. And that's why there's Rosetta 2, the emulator framework that runs Intel apps on M1 Macs.

Do I have to install Rosetta 2 myself?

Do you use a Mac, iMac, Mac mini, MacStudio, a MacBook Pro or MacBook Air with an Apple chip, then the first time you try to open an Intel app, this message may appear: "To open from [app name] you need to install Rosetta. Install now?“ – This is neither an error nor a scam by the providers of the app to be opened. In fact, Rosetta 2 doesn't necessarily come pre-installed when you get a new Mac with M1, M1 Pro, M1 Max or M1 Ultra uses. It is only pulled from the Apple servers if you want to use "old" software written for the x86 architecture.

Rosetta 2 is not necessarily preinstalled in macOS 11 Big Sur and macOS 12 Monterey. Therefore, you may be asked if you want to install it when you try to open an x86 app. Image source: Apple.com
Rosetta 2 is not necessarily preinstalled in macOS 11 Big Sur and macOS 12 Monterey. Therefore, you may be asked if you want to install it when you try to open an x86 app. Image source: Apple.com

Which of my apps require Rosetta 2 on Mac?

The information window shown above tells you when you start the app whether you need Rosetta or not. However, you can also find out in advance whether an app is only available in the version written for Intel chips or whether it has already been adapted for Apple Silicon. You can check this directly under macOS as follows:

  1. Navigated in Finder to the corresponding app (probably in the programs folder)
  2. Right-click on it and select "Information" (or in the menu bar File -> Information)
  3. Under "Type" there are now two options: "Program (Intel)" requires Rosetta, "Program (Universal)" is also made for the M1 chip

Can I open M1 compatible apps with Rosetta?

For the basic version of an app that is already adapted to the "Apple Silicon" SoC and its ARM architecture, it doesn't make much sense to use Rosetta 2 at first. However, there are a number of plugins for many programs from the web browser to music production to photo editing. And of course it can happen that older plugins are not (yet) adapted to the M1 chip and its ARM processor architecture. So it can be worthwhile to run a universal app under Rosetta because of the plugins. To do this, go to the program information again (see above) and activate the check mark “Run with Rosetta”.

If you're using a universal app that works natively on Apple Silicon's ARM architecture, you can still use Rosetta to run it. This is useful if e.g. B. Plugins or add-ons are written exclusively for x86 processors.
If you're using a universal app that works natively on Apple Silicon's ARM architecture, you can still use Rosetta to run it. This is useful if e.g. B. Plugins or add-ons are written exclusively for x86 processors.

More information about the topic

You can find more information and the sources for this article with these links:

  • Official support document HT211861 from Apple: View here
  • Wikipedia post on Rosetta with more details: Read here
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In the Sir Apfelot Blog you will find advice, instructions and reviews on Apple products such as the iPhone, iPad, Apple Watch, AirPods, iMac, Mac Pro, Mac Mini and Mac Studio.