Rosetta keeps translated copies of every Intel app you have run. How much, and what to do
On Apple silicon, Rosetta caches translated Intel code in a protected system folder. What it costs, how to see which apps need it, and why not to delete it.
When you run an app built for Intel Macs on Apple silicon, Rosetta translates it and keeps the translation, so the next launch is fast. Those translations live in a system folder, /private/var/db/oah. It is usually modest, from a few hundred MB to a couple of GB, depending on how many Intel apps you run.
Is Rosetta installed?
pkgutil --pkg-info com.apple.pkg.RosettaUpdateAuto 2>/dev/null && echo installed || echo "not installed"Which apps need it
Open System Information, go to Software, Applications, and look at the Kind column. Apps listed as Intel run through Rosetta. Replacing them with Apple silicon versions, where available, is the real fix.
Can you delete the cache or Rosetta?
The cache is protected by System Integrity Protection and managed by macOS, and there is no supported way to uninstall Rosetta. Deleting either by force is not worth the risk for the space involved. If you stop using Intel apps, the cache stops growing.
Why apps carry code for both chips: universal binaries. Running Windows apps: Windows apps on a Mac.
Common questions
What is the oah folder on a Mac?
It is where Rosetta keeps translated copies of Intel apps it has run on an Apple silicon Mac, at /private/var/db/oah.
Can I delete the Rosetta cache?
It is protected by macOS and managed automatically. It stops growing if you stop running Intel apps.
How do I see which apps use Rosetta?
Open System Information, go to Software, Applications, and look for apps whose Kind is Intel.