Can’t Open From Unidentified Developer? Fix It

If macOS blocks an app because it’s from an unidentified developer, the fix is to right-click (or Control-click) the app in Finder and select Open from the context menu, then confirm you want to open it. This bypasses the Gatekeeper warning for that specific app without disabling security for everything else. Below is the full breakdown of why this happens, how to do it safely, and what to do if the right-click trick doesn’t work.

Why macOS Blocks Unidentified Developers

Since OS X 10.7 Lion, Apple has included a security feature called Gatekeeper. Its job is to make sure only trusted software runs on your Mac. Gatekeeper checks two things: whether the app is signed with a Developer ID (a certificate from Apple) and whether that certificate is notarized by Apple. If an app lacks either, macOS shows the message “cannot be opened because the developer cannot be verified” or “macOS cannot verify that this app is free from malware.”

Most commercial and open-source apps are signed and notarized, so they open normally. But if you download a program from a website, a direct link, or a small developer who hasn’t paid Apple’s annual fee ($99/year for the Developer Program), the app will be flagged as unidentified. This is not a judgment on the app’s safety—it simply means Apple hasn’t vetted it.

How to Open an App From an Unidentified Developer

The safest and most direct method is to use the context menu:

1. Locate the app in Finder (usually in your Applications folder or Downloads).
2. Right-click (or Control-click) the app icon.
3. Select Open from the menu.
4. Click Open again in the confirmation dialog that appears.

This tells Gatekeeper to allow this one app to run, and it will be added to the allowed list. You only need to do this once. From then on, you can open it normally by double-clicking.

If you don’t see the Open option, or if the dialog doesn’t appear, try this alternative:

1. Go to System Settings (or System Preferences on older macOS).
2. Click Privacy & Security.
3. Scroll down to the Security section.
4. Look for a message that says “[App name] was blocked from opening because it is not from an identified developer.”
5. Click Open Anyway next to that message.
6. Confirm with your password or Touch ID.

This method works when the app was recently downloaded and the system has logged the block. If you’ve already dismissed the warning, you may need to re-download the app or use the right-click method.

What About the Terminal Command?

Another common fix is to use the spctl command in Terminal to remove the quarantine attribute. The command is:

sudo spctl --master-disable

This disables Gatekeeper entirely, which is not recommended because it leaves your Mac open to any unsigned software. A more targeted approach is to remove the quarantine flag from a single file:

xattr -d com.apple.quarantine /path/to/YourApp.app

This tells macOS that the file was not downloaded from the internet, so Gatekeeper won’t check it. However, this also removes the “downloaded from internet” warning that helps you know where the file came from. If you trust the source, this is a quick fix, but it’s safer to use the right-click method because it keeps the quarantine flag and just adds an explicit exception.

How to Check an App’s Signature Before Opening

Before you bypass Gatekeeper, you should verify that the app is what it claims to be. Here’s how:

1. Right-click the app and select Get Info.
2. Look at the General section—if there’s a “Last checked” date under the security info, it means the app was notarized.
3. If you see “No signature” or “Signature by unknown developer,” you can still open it, but you should be cautious.

You can also use the codesign tool in Terminal to verify the signature:

codesign --verify --deep --strict /path/to/YourApp.app

If it returns no errors, the code signature is valid. If it says “code object is not signed at all,” then the app has no signature, which is a red flag but not necessarily dangerous—some open-source projects don’t sign their builds.

Common Problems and Their Fixes

Problem: The right-click Open option is grayed out. This usually happens when the app is damaged or incomplete. Re-download the file and try again. If it’s a .dmg, make sure you’ve dragged the app to the Applications folder before opening it.

Problem: The Security section doesn’t show “Open Anyway.” This can happen if you’ve already tried to open the app and it failed, or if the app is not in the Downloads folder. Move the app to the Applications folder, then try again. If the message still doesn’t appear, restart your Mac and try the right-click method.

Problem: The app opens but crashes immediately. This is often a separate issue—maybe the app is incompatible with your macOS version, or it needs a component like Rosetta 2 (for Intel apps on Apple Silicon). Check the developer’s website for system requirements.

Problem: You see “The application can’t be opened” with no option to override. This is different from the unidentified developer warning. It usually means the app is 32-bit (macOS Catalina and later don’t support 32-bit apps) or the app is corrupted. In that case, you cannot fix it by bypassing Gatekeeper.

Is It Safe to Open Unidentified Apps?

Not always. The warning exists because unsigned apps can be modified by third parties without detection. A signed app guarantees that the code hasn’t been tampered with since the developer published it. An unsigned app could be a legitimate open-source tool, but it could also be malware disguised as a useful program.

Before you bypass the warning, ask yourself:

• Did you download it from the official website or a reputable source?
• Is the developer known? Search for reviews or mentions of the app.
• Does the app request unusual permissions (like accessibility or full disk access) that seem excessive for its function?
• Have you scanned the file with an antivirus or at least checked its size and icon?

If you’re unsure, you can run the app in a virtual machine or on a secondary Mac first. Also, keep your Mac’s built-in XProtect antivirus updated—it runs automatically and will block known malware even if you manually open an unsigned app.

How to Re-enable Gatekeeper Afterward

If you used the sudo spctl --master-disable command, you should re-enable it as soon as you’re done. In Terminal, run:

sudo spctl --master-enable

This restores the default security level (which is “App Store and identified developers”). You can also check the current status with:

spctl --status

If it says “assessments enabled,” Gatekeeper is on. If it says “disabled,” you need to re-enable it.

Frequently Asked Questions

Why does the app say “unidentified developer” even though I downloaded it from a well-known site?

Even large sites sometimes host unsigned builds, especially for beta versions or open-source projects. The developer may not have paid for an Apple Developer account, or they may have forgotten to sign the app. It doesn’t mean the site is malicious—just that Apple can’t verify the developer’s identity.

Can I open an unidentified app on a Mac with Apple Silicon (M1/M2/M3)?

Yes, the same steps work. However, if the app is not notarized, you may see a message that the app is damaged or that Apple cannot check it for malware. In that case, you can still use the right-click Open method to run it, but you may also need to install Rosetta 2 if the app is Intel-only.

What if I accidentally clicked “Move to Trash” when the warning appeared?

You can re-download the app from the original source. The warning doesn’t delete the file, but it does move it to the Trash. You can restore it from the Trash if you haven’t emptied it, but it’s safer to download a fresh copy to ensure it’s not corrupted.

Does opening an unidentified app void my Mac’s warranty?

No, it doesn’t affect your hardware warranty. Apple’s support policy may vary, but generally, opening unsigned software is not a warranty issue. However, if the app causes system instability, Apple Support might ask you to remove it before troubleshooting.

Is there a way to allow all apps from a specific developer?

Yes. After you open an app once using the right-click method, macOS remembers that you allowed it. For future apps from the same developer, you’ll still see the warning unless the developer signs them. There’s no built-in way to whitelist a developer by name, but you can use the spctl command with a custom rule if you’re comfortable with Terminal.

What is the difference between “unidentified developer” and “damaged and can’t be opened”?

“Unidentified developer” means the app lacks a valid signature. “Damaged” usually means the file is corrupted, incomplete, or has been tampered with. A damaged app will not open even if you bypass Gatekeeper. You need to re-download it.

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