If Firefox won’t open on your Mac and you see a message about Intel-based apps or Rosetta, this article will help you fix the problem. You might see a message like:

“Support Ending for Intel-based Apps. This version of Firefox will not open in a future release of macOS.”

This usually means your version of Firefox is outdated or running using Rosetta.

Why this happens

Apple is removing support for Rosetta, a tool that allows apps built for Intel-based Macs to run on Apple Silicon devices (such as M1, M2, and newer). If Firefox is using Rosetta or is an older version:

• macOS may show a warning
• Firefox may stop opening entirely on newer macOS versions

Check if Firefox is using Rosetta

If your macOS version still supports Rosetta, you can turn it off:

1. Quit Firefox.
2. Open the Applications folder.
3. Find Firefox.
4. Right-click (or Control-click) it and select Get Info.
5. Look for Open using Rosetta.
6. If checked, uncheck it.
7. Close the window and open Firefox again.

If Firefox opens normally, the issue is fixed.

Update Firefox to the latest version

If you don’t see the Rosetta option, or Firefox still doesn’t open, update to the latest version.

1. Visit the Firefox download page.
2. Download the latest version of Firefox.
3. Open the downloaded file.
4. Drag Firefox into the Applications folder.
5. Replace the existing version if prompted.
6. Open Firefox.

If you still see the message

• Make sure you are using the latest version of Firefox
• Restart your Mac after installing updates
• Check for macOS updates

If the problem continues, you can get help from Mozilla Support.

Frequently asked questions

What is Rosetta?

Rosetta is a compatibility feature from Apple that allows apps built for Intel-based Macs to run on newer Apple silicon devices (such as M1 and M2). To learn more, see this Apple support article.

Why is Rosetta being removed?

Apple is transitioning fully to Apple Silicon. Newer versions of macOS no longer support Rosetta, so apps must run natively.

Do I need Rosetta to use Firefox?

No. Current versions of Firefox are built to run natively on Apple Silicon and do not require Rosetta.

What happens if I keep using an old version of Firefox?

Older versions that rely on Rosetta may stop working on newer versions of macOS. Updating Firefox ensures it continues to work properly.

Will updating Firefox affect my data?

No. Updating Firefox does not remove your bookmarks, history, or saved data.

Related articles

• Update Firefox to the latest release
• How to download and install Firefox on Mac