Source: https://mactoolbox.app/glossary/quarantine-attribute

# What is the quarantine attribute on Mac?

By Nikhil Barik · Published November 3, 2026

## Quick answer

The quarantine attribute, com.apple.quarantine, is a small flag macOS adds to files you download. It tells Gatekeeper to check the app the first time you open it.

## What it is

It is an extended attribute stored with the file. Browsers, Mail and other apps set it on downloads. It records which app saved the file and when.

## Why it matters on a Mac

Because of this flag, a downloaded app triggers the first-open check. When that check fails you may see that the app is damaged, even though the file is not corrupt.

## How to check or change it on macOS

In Terminal, xattr -l /path/to/App.app lists attributes. xattr -cr /path/to/App.app removes all extended attributes from the app and its contents, including quarantine. Do this only for software you trust.

## How Toolbox handles it

Fix App Is Damaged shows the app's signing details and then clears the quarantine flag for you after you confirm.

## Frequently asked questions

**Is removing the quarantine flag safe?**

Only if you trust the source. It skips Gatekeeper's check for that app.

**Do all files get the flag?**

Files saved by apps that set it do. Files from other places, such as a USB stick, usually do not.

**What does xattr -cr do?**

It clears all extended attributes recursively, including quarantine.

## Tools mentioned

- [**Fix “App Is Damaged”**: Check who made an app that won’t open, then clear the download quarantine so macOS lets it run.](https://mactoolbox.app/app-is-damaged-cant-be-opened-mac)

## Keep reading

- [Fix “App Is Damaged”](https://mactoolbox.app/app-is-damaged-cant-be-opened-mac)
- [Gatekeeper](https://mactoolbox.app/glossary/gatekeeper)
- [Notarization](https://mactoolbox.app/glossary/notarization)