Source: https://mactoolbox.app/glossary/notarization

# What is notarization on Mac?

By Nikhil Barik · Published November 3, 2026

## Quick answer

Notarization is a check where a developer sends an app to Apple, which scans it for malicious content and returns a ticket. Gatekeeper uses that ticket to let the app open without a warning.

## What it is

Developers sign their app with a Developer ID, then upload it to Apple for notarization. Apple does not review the app's features. It checks for known malware and signing problems.

## Why it matters on a Mac

On current macOS, an app downloaded from outside the App Store normally needs to be signed and notarized to open without friction. Apps that are not may show a warning or be blocked.

## How to check it on macOS

In Terminal, run spctl --assess -vv /Applications/Name.app. For a notarized app the result mentions Notarized Developer ID.

## How Toolbox handles it

Fix App Is Damaged checks an app's signature and Gatekeeper status so you can see who made it. It can then clear the quarantine flag if you choose to trust the app. Only do this for apps from a source you trust.

## Frequently asked questions

**Does notarization mean an app is safe?**

It means Apple found no known malware at the time. It is not a full review.

**Why does my Mac say an app is damaged?**

Often the app is not signed or notarized in a way Gatekeeper accepts. The file is rarely corrupt.

**Do App Store apps need notarization?**

No. They go through App Review instead.

## 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)
- [Quarantine attribute](https://mactoolbox.app/glossary/quarantine-attribute)