How to Fix CoreServicesUIAgent Won’t Close on Mac

Macs are known for their security and prevention of viruses and malware. Part of that security comes from your macOS monitoring the applications you install on your system and ensuring that they are from legitimately approved developers and providers.

Security is great, but it can be extremely annoying when a security component such as CoreServicesUIAgent constantly opens a popup window and gets in your way. Fortunately, we can usually just kill the process using Activity Monitor but there are other things to try as well.

My name is Eric, and as a software engineer I know the importance of security, but I also know that sometimes security features can be too intrusive and keep you from using your computer the way you need to. I can show you how to solve this problem with CoreServicesUIAgent.

Keep reading below if you would like to see a number of methods you can use to solve this problem. I will go through each of them below and hopefully, they can help you to close the window.

How to Close Core Services UI Agent

If you’re seeing a popup window on your desktop stating that it is verifying an application, you are seeing the Core Services UI Agent. This popup window normally flashes on the screen very quickly and many times we don’t even notice it.

If the popup is staying on your screen and won’t close or it keeps popping up repeatedly, you are probably finding this very annoying and it may even be keeping you from using the application that it is trying to verify. This can be extremely frustrating.

The Core Services UI Agent is a security feature of your Mac, but in this case, there is something going wrong with it and we need to close it so that you can continue using your app as you normally would.

1. Wait it Out

You may have already been trying this but the first thing you’ll want to do is try to wait it out. As mentioned above, CoreServices UI Agent is a security feature of your Mac, so you want it to run and keep your Mac safe. 

Sometimes it can take a little longer than usual to run, so try waiting to see if the process can complete on its own. It can be irritating but once it completes normally you shouldn’t have to worry about it again.

If the popup window is getting in your way, you can try to minimize it to get it out of the way. Hopefully, it will complete on its own eventually. You can check on it every once in a while to see if it has been completed.

2. Quit the Application

If you have waited for a long while and still nothing is happening, you should try quitting the application and then starting it again to see if that makes a difference. The CoreServicesUIAgent process can sometimes get hung and restarting the app may fix the problem.

To quit the application that the Core Services UI Agent is hung on, try clicking the red button in the upper left corner of the app if possible. You can also go to the applications menu and select Quit <Application Name>

One more method you can use to close the app is to use the shortcut keys COMMAND+Q once you have the app selected on your desktop.

If those methods are not available to close the app because it has not yet gotten to a point where they are available, you can force the application to quit by clicking on the Apple menu in the upper left corner of your desktop and selecting Force Quit.

This will bring up the Force Quit Applications popup window. Find your application if it has not already been selected and then click on the Force Quit button.

After clicking the button you will be asked to confirm that you want to force the application to quit. Click on the Force Quit button again and the application will close.

Once you have gotten the application to quit, try starting it back up again and see if you have any issues. You may not see the CoreServicesUIAgent at all or you may see it briefly. If so, you should be good to go and hopefully will not see the agent again for this app.

If you continue to see the popup again and it will not close you will need to try another one of the solutions below.

3. End the CoreServicesUIAgent Popup Window

If quitting the application did not get rid of the popup you may need to end the CoreServicesUIAgent process to get it to close. In order to do this you will need to use Activity Monitor to find and end the CoreServicesUIAgent service. Just follow the steps below.

Step 1: Open Activity Monitor

Click on the Launchpad icon on the bottom left side of your screen.

Step 2: Start Activity Monitor

Type Activity Monitor in the search field of Launch Pad. Once you see Activity Monitor, click on it to start it up.

Step 3: Search for the CoreServicesUIAgent in Activity Monitor

Type CoreService in the Activity Monitor’s search field. You should then see the CoreServicesUIAgent in the list of processes.

Step 4: Quit the CoreServicesUIAgent process

To end the process, first, select it and then click on the x on the top left-center of the Activity Monitor window as shown below.

You will be asked to confirm that you want to quit the process. Click on Force Quit to quit the process. You will be asked to supply your admin password, which should be the password you use to log in to your Mac.

This should get rid of the CoreServicesUIAgent popup window and you should be good to go.

4. Restart your Mac

If you are still seeing the agent on your screen or it keeps coming back, you might want to try shutting your Mac down and starting it back up. I would recommend doing a complete shutdown and then starting it back up.

Do a complete shutdown by clicking on the Apple menu and then selecting Shut Down.

Wait for your Mac to completely shut down. Once you see the power shut off and you have waited for a few seconds, press the power button to start it back up. Restarting your system can often clear up many issues like this one.

Once your system has started back up, try starting the application that was causing the CoreServicesUIAgent window to come on and see if you still have the problem. Hopefully, this will resolve the problem.

5. Check for an Update to the Application

It could be that there is an issue with the application itself. Check to see if the application has any updates and if so install the updates. If you got your application from the AppStore, go to the updates section and check to see if there are any updates for the particular application.

6. Uninstall and Reinstall the App

If the Application doesn’t have an update available, you might try uninstalling the application and then reinstalling it. If the application came with an uninstall command or option you can use that. You could also uninstall it manually and even uninstall it using Mac Terminal if you want.

Once the application has been uninstalled, try installing it again and then starting the app up to see if it still has a problem getting by CoreServicesUIAgent.

7. Check for macOS Updates

It might sound like a long shot, but a macOS update can often solve strange problems with your system. If your macOS is not up to date, it means that you don’t have the latest operating system installed on your Mac and you might miss critical fixes to bugs and other issues such as this one.

You can check for macOS updates by clicking on the Apple menu and looking for notifications beside System Settings.

Click on System Settings and you can then perform the update by clicking on Software Update Available and then clicking on Update Now.

Once the update has been completed, restart your system and see if the issue has been resolved.

8. Disable CoreServicesUIAgent

If this issue continues to give you problems, it is possible to disable CoreServicesUIAgent. I wouldn’t normally recommend this because CoreServicesUIAgent is one of the security tools that keeps your Mac safe from malware and viruses. 

CoreServicesUIAgent checks each application the first time it is run, to make sure that it comes from a verified and legitimate developer. This helps to keep applications safe and make them traceable back to the developer which in turn prevents the development of malicious software.

So, turning the agent off can be risky and open your system up to software that could damage your Mac. This is why I suggest against this, but in some situations, it can be your only option. If you decide to go this route, make sure that you have backed your system up prior to running any new software without the agent.

Also, once you have done what you need to do, make sure you turn the agent back on so that it can protect you when other apps are installed and run going forward. Use the following steps to disable and then re-enable CoreServicesUIAgent.

Step 1: Open Mac Terminal

Use your preferred method to start up Mac Terminal.

Step 2: Disable CoreServicesUIAgent

Type the following command to disable the agent.

sudo spctl –master-disable

You will need to enter your admin password after typing the command and hitting the return key. This will be the same password you use to login to your machine.

Step 3: Start your Application

You can now start up the application that is causing the CoreServicesUIAgent popup window to appear. Your application should start up and run without any issues.

Step 4: Enable CoreServicesUIAgent

Now that your application is up and running, you should re-enable the agent so that you are still protected from malware and viruses from other applications. If you do not re-enable it, your system will be at risk. To enable just type the following command in Mac Terminal.

sudo spctl –master-enable

You may need to enter your password again depending on how long ago you entered it for the command to disable. Once completed the CoreServicesUIAgent will once again be enabled and your system will now be protected.


Having the CoreServicesUIAgent popup window stuck on your screen is not only annoying, but it can also keep you from using the application that it is trying to verify. As you can see above, there are various methods you can use to end or close this popup window so that you can use your application.

I hope the information above has helped you to be able to close the CoreServicesUIAgent popup window and allow you to run your application. As usual, let me know if you have any questions or comments. I would love to have your feedback.

Leave a Reply

Your email address will not be published. Required fields are marked *