Open apps safely on your Mac

macOS includes a technology called Gatekeeper that's designed to ensure that only trusted software runs on your Mac.

The safest place to get apps for your Mac is the App Store. Apple reviews each app in the App Store before it’s accepted and signs it to ensure that it hasn’t been tampered with or altered. If there’s ever a problem with an app, Apple can remove it from the store quickly.

If you download and install apps from the internet or directly from a developer, macOS continues to protect your Mac.

  • When you install Mac apps, plug-ins and installer packages from outside the App Store, macOS checks the Developer ID signature to verify that the software is from an identified developer and that it has not been altered.

  • By default, macOS Catalina and later also require software to be notarised, so you can be confident that the software you run on your Mac doesn’t contain known malware. An app that has been notarised by Apple indicates that Apple has checked it for malicious software and none was detected.

  • Before opening downloaded software for the first time, macOS requests your approval to make sure you aren’t misled into running software you didn’t expect.

Running software that hasn’t been signed and notarised may expose your computer and personal information to malware that can harm your Mac or compromise your privacy.

If your Mac displays an alert when you open an app

The warning messages displayed below are examples, and it's possible that you could see a similar message that isn't displayed here. Please use caution if you choose to install any software for which your Mac displays an alert.

Alert that the app was downloaded from the Internet

The first time you open a new app from an identified developer that you downloaded outside the App Store, your Mac asks if you’re sure you want to open it.

Alert that Apple cannot check the app for malicious software


If Apple can’t check an app for malicious software:

Alert that the app developer cannot be verified

If the app developer can’t be verified and – in macOS Catalina and later – the app hasn’t been notarised by Apple, macOS can’t verify that the app is free of malware.

Alert that the app wasn’t downloaded from the App Store

If your Privacy & Security settings allow apps from only the App Store, macOS won’t open an app that wasn’t downloaded from the App Store.

Alert that the app will damage your computer or the app is damaged

  • If macOS detects that software has malicious content or its authorisation has been revoked for any reason, your Mac will notify you that the app will damage your computer.

  • If macOS detects that software has been modified or damaged, your Mac will notify you that the app can’t be opened. The app may be broken or corrupted, or it may have been tampered with.

  • You should move this app to the Bin and, if available, tick “Report malware to Apple to protect other users”.

If you want to open an app that hasn’t been notarised or is from an unidentified developer

Running software that hasn’t been signed and notarised may expose your computer and personal information to malware that can harm your Mac or compromise your privacy.

If you’re certain that an app that you want to open is from a trustworthy source and hasn’t been tampered with, you may be able to temporarily override your Mac security settings to open it.*

  1. Open System Settings.

  2. Click Privacy & Security, scroll down and click the Open Anyway button to confirm your intent to open or install the app.

  3. The warning prompt reappears and, if you’re absolutely sure you want to open the app anyway, you can click Open.

The app will now be saved as an exception to your security settings, and you can open it in the future by double-clicking it, just as you can any authorised app.

* If you’re prompted to open the app in Finder and you’re sure that you want to open it despite the warning, you can control-click the app, choose Open from the menu, then click Open in the dialogue that appears. Enter your admin name and password to open the app.

Change the app security settings on your Mac

  1. In System Settings, click Privacy & Security. Then scroll down to Security.

  2. Under “Allow apps downloaded from”, select an option: *

    • App Store: Only allow apps that have been downloaded from the App Store

    • App Store and identified developers: Allow apps that have been downloaded from the App Store and from developers identified by Apple.

* These settings may not be available if your Mac is managed by a system administrator or IT department.

Privacy protections

macOS has been designed to keep users and their data safe while respecting their privacy.

Gatekeeper performs online checks to verify whether an app contains known malware and whether the developer’s signing certificate is revoked. We have never combined data from these checks with information about Apple users or their devices. We do not use data from these checks to find out what individual users are using on their devices.

Notarisation checks whether the app contains known malware using an encrypted connection that is resilient to server failures.

These security checks have never included the user’s Apple ID or the identity of their device. To further protect privacy, we don’t log IP addresses associated with Developer ID certificate checks, and we make sure any collected IP addresses are removed from logs.

Information about products not manufactured by Apple, or independent websites not controlled or tested by Apple, is provided without recommendation or endorsement. Apple assumes no responsibility with regard to the selection, performance or use of third-party websites or products. Apple makes no representations regarding third-party website accuracy or reliability. Contact the vendor for additional information.

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