Install Rosetta only from Apple’s prompt or official softwareupdate command. Third-party “Rosetta installers” are scams — Rosetta is a system component, not a standalone download from random websites.
What you will achieve
Install Rosetta 2 when macOS prompts you on Apple Silicon — so Intel-only applications and installers run correctly — or install manually from Terminal if you dismissed the dialog.
Rosetta does not apply to Intel Macs — they run x86_64 software natively. This guide is for M-series Macs only unless you are verifying a Universal app’s architecture.
1) When the prompt appears
Launch an Intel-only app or open an x86_64 installer (.pkg or .app without arm64 slice). macOS shows: “You need to install Rosetta to open [app].” Click Install, authenticate, wait for completion — typically under a minute on fast internet.
No restart required. Relaunch the app immediately after install finishes.
2) If you clicked Not Now
Open Terminal (Applications → Utilities → Terminal) and run:
softwareupdate --install-rosetta --agree-to-licenseEnter admin password when prompted. This is the same component as the GUI installer — Apple’s official path for headless or dismissed prompts.
3) Confirm Rosetta is active
Launch the Intel app again — no second prompt. In Activity Monitor, enable View → Columns → Kind; Intel processes show Intel while running under translation. Quick check:
pgrep -q oahd && echo "Rosetta daemon running"oahd is the Rosetta translation daemon on Apple Silicon.
4) When to accept vs seek native apps
Accept Rosetta for legacy tools without arm64 builds — old Adobe installers, niche enterprise apps, x86-only CLI binaries. Prefer Universal or arm64 updates when available: better performance and lower RAM use. Check the vendor site before defaulting to Rosetta long term.
5) Managed Macs
Organisations may pre-install Rosetta via MDM or block user installs. If the prompt fails with policy error, request IT deployment. Do not copy Rosetta binaries from another Mac — code signing and SIP prevent that working reliably.
6) Performance expectations
Translated apps use roughly 10–30% more memory than native arm64 builds. Acceptable for occasional tools; painful for daily heavy apps like video editors — chase native updates. Intel Mac users never see this prompt and should not install anything called Rosetta manually.
7) Reinstall if translation crashes
Rare oahd crashes: rerun softwareupdate --install-rosetta --agree-to-license. Do not delete system Rosetta files in /Library/Apple or /usr/libexec/oah — breaks all Intel software until reinstall macOS.
Verify
Target Intel app launches without Rosetta prompt; Activity Monitor shows Kind Intel for that process; oahd daemon present.