macOS App Won't Open — Application Cannot Be Opened Fix

What Does This Error Mean?

When a Mac app refuses to open, you might see messages like 'The application cannot be opened' or 'App is damaged and cannot be opened.' macOS has security features called Gatekeeper that block apps from unknown developers — this is the most common cause. Other causes include a corrupted app file, wrong macOS version, or the app crashing silently on launch.

Affected Models

MacBook Air
MacBook Pro
iMac
Mac Mini
Mac Studio
Mac Pro

Common Causes

Gatekeeper is blocking the app because it was downloaded from outside the App Store
The app was downloaded from the internet and has a 'quarantine' flag blocking it from running
The app requires a newer version of macOS than you have installed
The app's support files have become corrupted and need to be deleted
The app is not compatible with Apple Silicon (M1/M2/M3) and needs Rosetta 2 installed

How to Fix It

Try right-clicking to open. Instead of double-clicking the app, right-click it and choose Open. A dialog will appear asking if you are sure. Click Open.

This bypasses Gatekeeper's block for unverified apps and adds an exception so it will open normally in the future. You only need to do this once per app.
Allow the app in Privacy and Security settings. Go to System Settings > Privacy and Security. Scroll down to find a message about the blocked app and click Open Anyway.

After being blocked, macOS shows a message here for a short time. If you do not see it, try to open the app first to trigger the block, then come back here.
Install Rosetta 2 (Apple Silicon Macs only). If you have an M1, M2, or M3 Mac and an app asks for Rosetta, click Install in the dialog that appears. Or open Terminal and type: softwareupdate --install-rosetta

Rosetta 2 lets your M-series Mac run apps built for older Intel Macs. Many older apps still need it.
Delete the app's preference files. Open Finder > Go > Library (hold Option while clicking Go). Navigate to Preferences and delete any files that start with the app's name. Then try opening the app again.

Corrupted preference files can prevent an app from launching. Deleting them makes the app start fresh, as if you just installed it.
Delete and reinstall the app. Drag the app from Applications to the Trash. Empty the Trash. Then reinstall the app from the App Store or the developer's website.

A fresh install replaces any corrupted application files.

When to Call a Professional

You should not need professional help for an app that will not open. If the app is important and none of these steps work, contact the app developer's support team. They can confirm compatibility with your Mac model and macOS version.

Frequently Asked Questions

Is it safe to open an app that Gatekeeper blocked?

It depends on where you got the app. If you downloaded it from the official developer's website or the App Store, it is generally safe to bypass the warning. If you found it through a random web search or a piracy site, do not open it — it may be malware.

What does 'App is damaged and can't be opened. You should move it to the Trash' mean?

This usually means the app has the macOS quarantine flag and is being blocked by Gatekeeper. Despite the wording, the app is probably not actually damaged. Try the right-click > Open method, or remove the quarantine flag via Terminal by typing: xattr -cr and dragging the app into Terminal.

Why did an app suddenly stop working after a macOS update?

macOS updates sometimes change security requirements or break compatibility with older app versions. Check if an updated version of the app is available. Sometimes the developer needs a few days or weeks after a major macOS update to release a compatible version.