Fix Error Code 10661: App Can’t Be Opened on Mac

You’re happily clicking an app on your Mac, maybe ready to edit a photo or dive into a new game, and—uh oh! A message pops up out of nowhere: Error Code 10661: The app can’t be opened. What does that even mean? Is your Mac mad at you? Did the app just ghost you?

Don’t worry! We’ve broken things down into simple steps. You’ll be back in action faster than you can say “Command + Q.”

TLDR (Too Long, Didn’t Read)

Error Code 10661 usually means the app you’re trying to open isn’t launching properly. Maybe it’s not compatible with your macOS, or it could be corrupted. Try restarting your Mac, updating the app, or reinstalling it. If all else fails, changing permissions or checking Rosetta might help.

What Is Error Code 10661?

This message shows up when your Mac tries to open an app, but something just isn’t right. Think of it as your Mac saying, “I tried, but nope. Not today!”

You usually see it after:

• Updating macOS
• Installing an app from a non-App Store source
• Moving apps from another Mac via Time Machine
• Trying to open outdated software

What Causes It?

The most common reasons are:

1. Incompatible apps: Some older apps just don’t work with the latest macOS.
2. Missing permissions: Your Mac might block an app it can’t verify.
3. Corrupted files: If something went wrong during install, boom—error city.
4. No Rosetta: Certain apps need Rosetta to run. Without it, they just won’t start.

Easy Fixes to Try First

Let’s start with the quick stuff. These won’t take more than a few minutes.

1. Restart Your Mac

Classic, right? But you’d be surprised how often it works.

1. Click the Apple logo in the top-left corner.
2. Select Restart…
3. Wait for it to reboot and try opening the app again.

2. Update macOS and the App

Sometimes staying current makes all the difference.

• Go to System Settings > General > Software Update.
• Install any available updates.
• Also check if the app has a newer version available.

3. Reinstall the App

If the app is corrupted or something didn’t install right, this fixes that.

• Open your Applications folder.
• Right-click the app and choose Move to Trash.
• Empty the Trash.
• Download and install the app again from a trusted source.

Still Locked Out? Try These Next

4. Check Permissions

Sometimes your Mac won’t play nice unless it knows the app is safe.

1. Right-click the app and choose Get Info.
2. Scroll down to Sharing & Permissions.
3. Make sure your user account has Read & Write access.
4. If not, click the lock icon, enter your password, and change the permissions.

5. Open With Rosetta (For Intel-based Apps on M1/M2)

If you’re using an M1 or M2 Mac, some older apps need Rosetta to run.

1. Find the app in Finder.
2. Right-click, choose Get Info.
3. Check the box that says Open using Rosetta.

If you don’t see that box, the app might already be universal or Apple Silicon optimized.

6. Run the App from Terminal

If the GUI fails, Terminal might just get it going.

1. Open the Terminal app.
2. Type this: open /Applications/AppName.app
3. Replace AppName with the actual app name.

If it runs here, the problem might be with Dock shortcuts or Launchpad.

7. Reset Launch Services

Launch Services manage which apps open what. If it gets confused, trouble follows.

1. Open Terminal.
2. Type and hit enter:

    
   /System/Library/Frameworks/CoreServices.framework/
   Frameworks/LaunchServices.framework/Support/lsregister 
   -kill -r -domain local -domain system -domain user
   

3. Restart your Mac.

Bonus Trick: Safe Mode

This starts your Mac with only the essential stuff running.

1. Intel Macs: Restart and hold Shift as it boots up.
2. Apple Silicon Macs: Shut down the Mac, then press and hold the power button until you see “Loading startup options.” Choose your disk, hold Shift, then click Continue in Safe Mode.

Try to open the app in Safe Mode. If it works, the issue is likely caused by a background process or login item.

Still No Luck? Contact Support

If none of these fixes work, it might be time to call in the pros.

• Contact the app’s developer. Most have a support page or email.
• Visit Apple Support if you think it’s a system issue.
• Take your Mac to an Apple Store or authorized service provider.

Quick Recap

Here’s a speedy check-list of all the solutions:

• ✅ Restart Mac
• ✅ Update macOS and the app
• ✅ Reinstall the app
• ✅ Check permissions
• ✅ Open using Rosetta
• ✅ Try Terminal
• ✅ Reset Launch Services
• ✅ Use Safe Mode
• ✅ Contact Support

Final Thoughts

Error Code 10661 might seem scary, but most of the time, it’s a quick fix. Apps and updates sometimes don’t get along at first. Be patient, follow the steps, and you’ll usually solve it in minutes.

Now go open that app and enjoy whatever fun or productivity awaits you. 🎉