Mac Says App Can’t Be Opened From an Unidentified Developer? Fix It Safely

You download a useful app from a developer’s website, double-click it, and macOS stops you with a warning: the app can’t be opened because it is from an unidentified developer. The message looks alarming, and many people assume the app is dangerous or broken. In reality, this warning usually just means the app was not distributed through the App Store and its developer is not registered in the way macOS expects.

The protection behind this message is called Gatekeeper, and it is a sensible safety feature. The trick is knowing when it is safe to open the app anyway, and how to do it the correct way. This guide explains what the warning means, shows you the safe methods to open a trusted app, and helps you decide when you should walk away instead.

Quick Answer

When your Mac says an app can’t be opened because it is from an unidentified developer, right-click or Control-click the app, choose Open, then click Open again in the warning dialog. This tells Gatekeeper you trust this one app, and macOS will remember your choice for future launches. Only do this for apps you downloaded from the developer’s official website and fully trust.

What the Unidentified Developer Warning Means

Gatekeeper is a macOS security technology that checks apps before they run for the first time. Apps from the App Store are reviewed by Apple. Apps from outside the store can carry a digital signature from an identified developer, meaning a developer registered with Apple who signs their software. When an app has neither App Store review nor a recognised signature, Gatekeeper blocks the first launch and shows the unidentified developer warning.

The warning does not prove an app is harmful. Lots of small, honest developers, open-source projects, older tools, and company-internal apps trigger it. At the same time, the warning is doing its job: it forces a pause so you can think about where the app came from. Treat that pause seriously every time.

Different Warnings You Might See

• Unidentified developer: The app is unsigned or from an unregistered developer. You can usually open it with the right-click method if you trust the source.
• Apple cannot check it for malicious software: The app is signed but has not been notarised by Apple. The same right-click method often works, once you are sure of the source.
• The app is damaged and can’t be opened: This can mean a corrupted download, but it also appears for some unsigned apps. Download a fresh copy from the official site before trying anything else.
• The developer cannot be verified: Similar to the first message, handled through the Open Anyway option in System Settings.

Apple describes how Gatekeeper protects your Mac in its official support page on safely opening apps and understanding Gatekeeper on Mac, which is a helpful reference if you want the deeper detail.

Before You Open Any Blocked App

Safety checks come first. The bypass takes ten seconds, but deciding whether to use it deserves a minute of thought. Run through this list every time:

1. Did you download the app from the developer’s official website, and did you type that address yourself or reach it from a trusted link?
2. Were you expecting this download, or did the file arrive through a pop-up, an email attachment, or a site you do not recognise?
3. Does the app’s name and icon match exactly what you intended to install?
4. Is the app well known, with a real support page, reviews, or a long history?
5. Have you scanned the file if you have antivirus software installed?

If anything feels wrong, delete the file and empty the Trash. No app is worth risking your passwords, photos, and bank details. Genuine developers will never pressure you to bypass security quickly.

Method 1: Right-Click and Choose Open

This is the method Apple designed for exactly this situation. It creates a one-app exception without weakening security for everything else on your Mac.

1. Open the folder containing the app, usually Applications or Downloads.
2. Right-click or Control-click the app icon. Do not double-click it.
3. Choose Open from the shortcut menu.
4. A dialog appears with the same warning, but this time it includes an Open button. Click Open.
5. Enter your admin password or use Touch ID if macOS asks.
6. The app launches. From now on, you can open it normally by double-clicking, because macOS remembers your approval for this specific app.

If the app is inside a disk image, open it from the mounted image or move it to the Applications folder first, then use the same right-click method. If Open does not appear in the dialog, use the System Settings method below.

Method 2: Use Open Anyway in System Settings

On recent versions of macOS, a blocked app also leaves a record in your security settings, where you can approve it directly. This is the most reliable method on macOS Ventura, Sonoma, and Sequoia.

1. Try to open the app normally and dismiss the warning when it appears.
2. Open System Settings and go to Privacy and Security.
3. Scroll down to the Security section. You should see a message naming the app that was blocked.
4. Click Open Anyway next to that message.
5. Confirm by clicking Open, and enter your password or use Touch ID if asked.
6. The app launches and is approved for future use.

The blocked app message in settings does not stay forever, so do this soon after the failed launch. If nothing appears, try opening the app once more and check the settings again. Our walkthrough of how to allow apps from outside the App Store in macOS security settings covers these privacy options in more depth if you want to understand each setting before changing it.

What About the Terminal Command?

Older guides mention Terminal commands that disable Gatekeeper entirely or strip quarantine information from a file. Disabling Gatekeeper across the whole system removes a valuable layer of protection, and it is not needed for the occasional trusted app. The two methods above approve one app at a time, which is the right balance. Avoid any website that tells you to turn off all security as a first step, and never run a Terminal command you have copied from a forum unless you fully understand what every part of it does.

Common Mistakes to Avoid

• Bypassing the warning for unknown files: The single biggest mistake. If you do not know exactly where a file came from, delete it instead of opening it.
• Downloading the same app from a random mirror site: Unofficial download sites often bundle adware with real apps. Always use the developer’s own website.
• Approving an app with the wrong name: Malware sometimes imitates popular apps with slightly changed names or icons. Compare carefully before you click Open.
• Assuming the warning means the app is broken: The app is usually fine. Reinstalling repeatedly will not remove a Gatekeeper warning; approving the app properly will.
• Turning off all security to save time: Approving one trusted app takes seconds. Weakening the whole system to avoid it is never a fair trade.
• Ignoring repeated warnings for the same app: If an app you already approved triggers fresh warnings, remove it and download a clean copy. Something may have changed the app’s files.

How to Stay Safe With Apps From Outside the App Store

Plenty of excellent software lives outside the App Store, and using it safely is mostly about habits. Keep macOS updated, because security fixes arrive with system updates. Download only from official developer sites. Keep a current backup with Time Machine so a mistake is recoverable. Review which apps you have approved every few months, and delete tools you no longer use. Finally, be extra careful with apps that ask for your admin password during installation; a simple utility rarely needs it, so ask yourself why before typing it.

Conclusion

The unidentified developer warning is Gatekeeper asking you to slow down, not a verdict that an app is dangerous. If you trust the source, right-click the app and choose Open, or approve it with Open Anyway in Privacy and Security settings. If anything about the download feels off, delete it without a second thought. That simple habit — verify the source, approve one app at a time, never disable security wholesale — lets you run the software you need while keeping your Mac protected.

Frequently Asked Questions

Is it safe to open an app from an unidentified developer?

It can be safe if you downloaded the app from the developer’s official website and the app is well known and trusted. The warning means Apple has not verified the developer, not that the app is definitely harmful. If the source is unclear, do not open it.

Why does the warning keep appearing for the same app?

You may be opening a fresh copy from a disk image or Downloads folder each time instead of the approved copy in Applications. Move the app to Applications, approve it once there, and always launch that copy.

What is the difference between an identified and unidentified developer?

An identified developer is registered with Apple and signs their apps with a unique digital certificate. An unidentified developer has not done this, so Gatekeeper cannot confirm who made the app or whether it was altered after release.

Can I remove an app’s approval later?

Yes. Delete the app and its approval no longer matters, since the exception applies to that specific app. If you download it again later, Gatekeeper will ask again, and you can decide fresh based on the source.

Does this warning appear on iPhone or iPad?

No. iPhones and iPads only run apps from the App Store, so this Gatekeeper flow is specific to Macs, where installing software from the web has always been part of the platform.