Rosetta Mac App Translation Process Can Take 20 Seconds on First Launch [Updated]
Given that Apple's new M1 chip is designed based on ARM architecture, apps built for Intel's x86 architecture will need to be run through Apple's translation layer Rosetta 2 in order to function on Apple Silicon Macs, and this process can take some time.
Microsoft this week indicated that when launching any of its Mac apps for the first time on Apple Silicon Macs, the apps will bounce in the dock for approximately 20 seconds while the Rosetta 2 translation process is completed, with all subsequent launches being fast. This applies to Word, Excel, PowerPoint, Outlook, OneNote, and OneDrive.
Apple's developer documentation acknowledges this matter, noting that the Rosetta 2 translation process "takes time" and that users "might perceive that translated apps launch or run more slowly at times" as a result:
If an executable contains only Intel instructions, macOS automatically launches Rosetta and begins the translation process. When translation finishes, the system launches the translated executable in place of the original. However, the translation process takes time, so users might perceive that translated apps launch or run more slowly at times.
To avoid this translation process, developers can create a universal binary for their apps, allowing them to run natively on both Apple Silicon Macs and Intel-based Macs with one executable file. Microsoft is one of many developers in the process of doing so.
The first Macs with the M1 chip will begin arriving to customers Tuesday.
Update - November 14: Microsoft has since changed the wording of its support document, and now simply says that the first launch of each Office app "will take longer," rather than specifying 20 seconds. We’re told this is because Microsoft has not yet confirmed exact speeds on production hardware.