How to Fix “Cannot Open App from Unidentified Developer” on Mac?

Jamie Kaler Contribution

Rollins Duke Approved By

Published On May 25th, 2026 • 8 min read

If you happen to see a message like ‘this app is from an unidentified developer‘ while attempting to open some app or a DMG file, then do not panic at all! Such a thing happens when the app developer does not register with Apple or skips the verification process. Due to this, the Mac will not allow the app to open, as this is a result of an unidentified developer error at the time of installation. When such an error appears, the application will not install/launch, and this is when your Mac won’t open an unidentified developer.

For opening such an application from an unidentified developer on your Mac, you can just head over to “System Settings (or maybe System Preferences) > Privacy & Security”, and after that, scroll down to the “Security” section, then further press the “Open Anyway” button as soon as it shows up. Alternatively, if you are seeking a quick, temporary override, you can try to Control-click the application icon & then choose “Open from the shortcut menu to bypass the security warning simply for this particular launch.

Quite luckily, running & launching such apps is quite simple & straightforward, and this blog is going to describe the steps of doing this.

Why Does macOS Show the “Unidentified Developer” Warning?

Apple has a developer ID verification system and an app review process designed to minimise the risk of malware exposure on macOS. Apple encourages developers to register and submit their apps for review. It approves and signs applications only after checking them for harmful code such as malware.

You are likely to see an error each time you try installing an app from such an unidentified developer. A similar thing might happen when an approved developer releases an app, which Apple has not assessed yet. Conversely, if any app that was public before the process of registration & evaluation begins, then the same type of error will occur. Eventually, if Apple has not examined some application, they have no way to determine whether it is safe or not.

The warning “cannot open app from unidentified developer” does not imply that an app from an unrecognised developer is unsafe or malicious, or that it must be avoided from opening. To use such an application, a user just requires deactivating Gatekeeper fully or circumventing it if the user is positive that the software is from a trusted source. So, you can give the following fixing options a try when you can’t launch any application from an unauthorised developer on your Mac.

If macOS shows different related security warnings instead, read the article to fix the “Apple cannot check it for malicious software” error on.

Manual Methods to Fix “Cannot Open App from Unidentified Developer”

Here, you are going to learn why the “this application cannot be opened because it is from an unidentified developer” error happens on a Mac, and how you can resolve this issue promptly.

Fix 1: Try Right-clicking for Opening the Unidentified App

One of the simplest methods of running such an app from an unidentified developer on your Mac is to first right-click on that app to open it that way. This helps in bypassing the standard security settings and launching that application as usual through the shortcut menu.

Follow the steps to open the app:

Open the Application folder from the Finder.
Locate the app you want to launch.
Hold the Control key and click the application.
Select Open from the shortcut menu.
Next, press Open again when prompted.

After this, you can simply double-click that application to open it later, like any other authorised program, & this will get stored safely for future access.

Fix 2: Remove the Quarantine Attribute using Terminal

When you download a file from the Internet with the help of HTTP/HTTPS via AirDrop, the app, which downloads it, tends to link a separate flag to it. Afterwards, Gatekeeper could use the com.apple.quarantine attribute for deciding if that app should be checked or blocked again. If you wish to bypass Gatekeeper or even avoid any unintended texts which deter you from using any unauthorised apps, perform the following steps:

Open the Terminal by navigating to Application > Utilities > Terminal.
Check whether the quarantine attribute exists on the app by running:

xattr /path/to/your/app
Instead of typing the path manually, drag and drop the app to the Terminal window, and it will paste the full path automatically. Press Enter. If the com.apple.quarantine appears in the output; the file is quarantined.
To remove the quarantine attribute, run the following command:

sudo xattr -r -d com.apple.quarantine /path/to/your/app
Leave a space after entering the command, drag and drop the app into the terminal to fill the path automatically, and press Enter.
Type the administrator password when prompted and press Enter again.
Try launching the app again. It will open the app without any security warning.

What the flag means: -r applies the change recursively to all files inside the application package. -d deletes the specified attributes. Together, these commands remove the quarantine attribute from the app and all files contained within it.

Fix 3: Fix “Cannot Open App from Unidentified Developer” Using Open Anyway

If you wish to authorise or open a restricted app, you can do so by pressing the “open anyway” button, which is in “Privacy & security.”

Here are the steps you can follow to launch such applications from unidentified/unspecified developers:

Click the Apple menu and then select System Settings.
Go to Privacy & Security.
Scroll down to the Security section.
Click Open Anyway beside the blocked application message.
Confirm by clicking Open.

Note: The “Open Anyway” option is available only for 1 hour after you attempt to launch the application.

Fix 4: Disable Gatekeeper via Terminal (Advanced)

If the previous three fixes did not work, you can temporarily disable the Gatekeeper system-wide to unlock the hidden Anywhere option in the security settings. This is how you can launch such apps. Since the “Anywhere” option is hidden by default, you would need to disable Gatekeeper to reveal it. If the problem persists as usual, you can alter the “Security & Privacy” setting to enable applications installed from anywhere.

Security Warning: Disabling Gatekeeper removes a critical layer of protection from your Mac. Only use this method if you are completely sure that the app is safe and from a trusted source. Re-enable Gatekeeper immediately after launching the app.

Follow the steps below to enable your Mac to install applications from unknown developers via Terminal:

Open Terminal by navigating to Application > Utilities > Terminal.
Type the following command and press Enter:

sudo spctl –master-disable
When prompted, enter the administrator password and press Enter.
Now, open System settings > Privacy & Security > Scroll to the Security section.
Finally, check the Anywhere option that’s under Allow apps downloaded from.
Launch the app as normal. It should now open without any security warning.

sudo spctl –master-enable

Why this step is crucial: leaving Gatekeeper disabled makes your Mac susceptible to viruses, so always be sure to turn off the “Anywhere” option after you have launched the application.

FAQs

Q) How can I allow my Mac to open an application from an unidentified developer?

A) To do this, first open “System Preferences,” then go to the “Security & Privacy” section, press the “lock” icon, and enter your password to make the changes. Next to this, you need to alter the settings for “Allow apps downloaded from” to “App Store and identified developers” from Apple Store.

Q) What does the unidentified developer warning on a Mac mean?

A) When you attempt to open an app which is not Apple-authorised or recognised by a developer, you would get such a “cannot open app from unidentified developer” warning dialogue. This definitely does not mean that something’s wrong with the app. For instance, some developers created apps before Apple introduced developer ID registration requirements.

Q) How is it possible to install a DMG file from an unidentified developer?

A) You can open a .dmg file easily by double-clicking on it, and check the contents of that DMG file. The contents of the file would typically load in a window that would display the directory name inside the Finder pane. For installing the app (that may need an administrator password during the process), you need to drag it from the DMG window into the Applications category. Once you are done with the copy procedure, simply wait for the copying to finish.

Pro Tip: You can safely download MacUncle Tools from the official website for a secure installation experience. The downloading of apps from trusted developers and official sources helps to avoid the unidentified developer warning on Mac.

Ending Thoughts

Here’s a quick ending note about the “cannot open app from unidentified developer” notification. This pop-up doesn’t necessarily indicate that the software is harmful. If data losses take place because of such an error, you must act promptly.