10661 Error on Mac

What is error code 10661 on Mac?

The 10661 error, also known as kLSExecutableIncorrectFormat, appears on Mac when there’s an incompatibility between an app you’re trying to open and your computer’s configuration. This could happen if your macOS or hardware doesn’t support the app’s format, or if Apple doesn’t recognize the software as being from an identified developer. In some cases, error code 10661 can also occur when you attempt to install an app using a guest profile.

Unfortunately, error 10661 isn’t the only issue you might face on a Mac. If you depend on Terminal for your daily tasks, our guide to resolving the “command not found” error on Mac can help you troubleshoot quickly and avoid unnecessary frustration.

What causes error code 10661 on Mac?

There are several possible reasons why the application can’t be opened on Mac. The app may be incompatible with your current version of macOS, or your Mac’s settings may restrict its launch. The file could also be incompatible with macOS, such as being in .exe format or being unverified software downloaded from the Internet that Apple doesn’t recognize.

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How to fix “application cannot be opened” on Mac?

There are simple fixes that anyone can try to resolve error 10661, as well as more advanced solutions for tech-savvy users. Start by checking that the app is compatible with your Mac. Next, try updating or reinstalling it. We also recommend reviewing the permissions for your Mac’s disk. If the issue persists, consider running Apple.

With our tips, the annoying “you don’t have permission to open the application” message will soon be a thing of the past. Here, we’ll walk you through resolving error 10661 step by step.

1. Check for app updates

First off, we recommend updating the app you want to open to the latest version. This helps ensure it’s free of bugs and fully compatible with your current version of macOS.

Check if any updates are available by following these steps:

1. Launch the Mac App Store.
2. In the sidebar, go to the Updates section.
3. Find the app that’s triggering the error 10661 in the list.
4. Hit the Update button next to it.

2. Verify app installer format

A common cause of error 10661 is attempting to install an app that isn’t compatible with your Mac. While there may be various reasons for this incompatibility, our experience shows that the installer format is often the main issue.

Here’s how to check the format of your app installer:

1. Open Finder on your Mac.
2. Go to the Downloads folder (or the folder where the installer is located).
3. Check the format of the installer at the end of the file name.
4. It should be a .dmg file to be compatible with macOS.

3. Make sure the app is compatible with macOS

Checking the installer format isn’t the only way to determine if an app is compatible with macOS. You might have downloaded an app intended for Windows or for a different version of macOS than the one installed on your device.

Use our practical tips to verify whether the app is compatible with your macOS version:

1. Go to the app’s official website to find its software requirements. We use MacKepeer as an example.
2. Click the Apple icon in the menu bar.
3. Select About This Mac from the dropdown menu.
4. In the new pop-up window, check your macOS version and compare it to the app’s system requirements.

4. Adjust Mac security settings

Your Mac’s advanced security systems might be preventing the app from opening. Before making changes, we advise considering whether they’re truly necessary, as these protections are in place for your safety. If you’re certain you want to continue, here’s how to proceed:

1. Click the Apple icon in the menu bar.
2. Choose System Settings.
3. Scroll down the sidebar to find Privacy & Security.
4. Under Security, click the Open Anyway button. This will allow you to run an app from an unidentified developer on your Mac.

For additional Preferences errors on Mac, consult our comprehensive guide.

5. Reset app permissions

As mentioned earlier, lacking the proper app permissions can lead to issues, such as the frustrating 10661 error when opening certain apps. Fortunately, based on our own experience, you can usually resolve this problem quickly by following these steps:

1. Go to the Apple menu from the menu bar.
2. Select System Settings.
3. Scroll down the left panel and click on Privacy & Security.
4. On your right, select Accessibility.
5. Use the + and - icons to delete and then re-add the app you want to open.

6. Reinstall or repair the app

If updating the problematic app to the latest version doesn’t resolve the issue, try uninstalling and reinstalling it. While this might seem like an extreme measure, we often find it to be an effective way to fix persistent 10661 errors.

1. Open Finder.
2. Go to the Applications folder.
3. Find the problematic app and right-click on it.
4. Click Move to Trash/Bin.
5. When prompted, enter your admin password, then click OK.
6. Go to your Mac’s Trash and click Empty.
7. Hit the Empty Trash button to confirm.
8. Finally, download the app from its website or the Mac App Store and follow the on-screen instructions to reinstall it.

7. Check disk permissions on Mac

If your Mac won’t open an app, the root cause might be a system issue rather than a problem with the app itself. In situations like this, we recommend using Disk Utility, a built-in tool in macOS designed to diagnose and repair disk-related problems in Mac.

Follow our tips below to resolve disk issues on your Mac:

1. Launch Finder.
2. Go to the Applications folder.
3. Open the Utilities folder, then launch Disk Utility.
4. Select your Mac’s startup disk in the sidebar.
5. Hit the First Aid button at the top.
6. Wait until Disk Utility has checked and fixed any issues.

We also suggest following this advice when looking for how to fix S.M.A.R.T. error on a hard disk on a Mac.

8. Update macOS

If you suspect macOS compatibility issues are preventing an app from opening on your Mac, we recommend updating your operating system to the latest version. This can also resolve existing software bugs and improve overall performance.

Here are the steps for upgrading your macOS:

1. Go to the Apple menu in the menu bar.
2. Select System Settings from the dropdown menu.
3. Choose General on the left-side panel.
4. Click Software Update on the right.
5. If an update is available, click Update Now.
6. Follow the on-screen instructions to complete the update.

9. Boot into safe mode and run diagnostics

Our final recommendation is for users who are comfortable with advanced troubleshooting. Apple provides a startup option called Safe Mode, which lets you diagnose and resolve persistent software issues that may arise when you start up your Mac normally.

We explain how to enter Safe Mode to run Apple Diagnostics below:

1. Click the Apple icon in the menu bar.
2. Choose Shut Down from the dropdown menu.
3. Press the power button on your keyboard until the startup options appear on your screen.
4. Press and hold Command+D simultaneously.
5. Release all keys when your machine starts powering on.

Ultimate advice on fixing an application that cannot be opened on Mac

Why does the app you need most always fail at the most inconvenient time? The 10661 error on Mac can be frustrating, but it’s usually straightforward to resolve. Start by checking your Mac’s permissions and compatibility, update your macOS if needed, and use built-in tools such as Disk Utility or Apple Diagnostics for further troubleshooting.

If these steps don’t resolve the issue, consider MacKeeper, the leading Mac optimization solution trusted by millions. Developed by Clario Tech, MacKeeper includes Premium Services, giving you access to a team of expert technicians available 24/7.