Safely open apps on your Mac

1. The app was not downloaded from the Mac App Store

If you've set up your Mac to allow only apps from the App Store and you try to install an app from another source, your Mac will display a message that the app isn't from the App Store.

Open System Preferences > Privacy & Security.

Enable apps downloaded from "App Store and verified developers."
You'll need your administrator password or Touch ID.

Congratulations, you can now run apps from the Mac App Store and verified developers.

If that doesn't help, check out this article on disabling Gatekeeper and performing a "dequarantine."

2. Application from an unknown developer.

If your Mac is set up to allow installation of apps from the App Store and verified developers, and you try to install an app that isn't registered with Apple, you'll also see a warning.

Hold down the Control (or Ctrl) key ⌃ and click the program icon, then select "Open" from the context menu.
Or first open the program by double-clicking, click "OK" in the warning that appears, then right-click the program, then select "Open" from the context menu.

In the dialog box, click "Open".

The program is saved in the list of exceptions from security settings, and in the future it can be launched by double-clicking (or from Launchpad), like any registered program.

This solution can be applied to the following error as well.

If this does not help, read the article on disabling Gatekeeper and performing "dequarantine".

3. The program could not be checked for malware.

Due to the introduction of mandatory application notarization procedure by Apple, macOS Catalina does not allow to launch an unverified application, even if it is signed by a registered developer. This results in the inability to launch the application.

In the System Preferences menu, click Security & Privacy and select General.

Click Confirm Login to launch the blocked program.

In the dialog box, click Open.

The program is saved in the list of exceptions from security settings, and in the future you can launch it by double-clicking (or from Launchpad) like any registered program.

This solution can be applied to the previous error as well.

If this does not help, see the article on disabling Gatekeeper and performing a "dequarantine".

4. The program is corrupted

If macOS detects a problem with an app — such as malicious content or modifications made after scanning — you'll be notified when you try to open the app and asked to move it to the Trash.

For a specific program, run in the terminal:

sudo xattr -r -c /Applications/LockedApp.app
Instead of "LockedApp.app" there should be a damaged application.

To disable checks globally, run in the terminal:

For macOS 10.12 - 10.15.7
sudo spctl --master-disable

For macOS 11 and newer
sudo spctl --global-disable

Learn more about disabling Gatekeeper

5. Error installing applications from Adobe.

This error occurs when installing Creative Cloud apps that use local installation packages.

This method does not work on Macs with Apple Silicon processors for TNT Team's 2021 Adobe builds.

Right-click the Install file and select "Show Package Contents" from the context menu.