How do I fix Sudoku app not closing on iMac?

To fix a frozen Sudoku app that will not close on your Mac, use Force Quit or Activity Monitor to shut it down. 

Use Force Quit

• Press Option + Command + Esc on your keyboard at the same time.
• Select the Sudoku app from the window that appears.
• Click the Force Quit button.
• Alternatively, click the Apple icon () in the top-left corner of your screen and select Force Quit, then choose the Sudoku app.
• Alternatively, hold down the Option key and secondary click (control click, right click) on the app icon in the Docn and select Force Quit. That is my go-to method.
• More info: How to force an app to quit on Mac - Apple Support

Use Activity Monitor

• Open Spotlight by pressing Command + Spacebar, type Activity Monitor, and press return.
• Find and select the Sudoku app in the process list.
• Click the X button in the upper-left corner of the Activity Monitor window.
• Click Force Quit to end the process.

Restart Your Mac

• If the app still will not close, click the Apple icon () and select Restart.
• If your entire screen is frozen, press and hold the Mac's power button (or Touch ID sensor) for up to 10 seconds until it turns off, then turn it back on

If Sudoku will not close on your 24-inch iMac, first press Command (⌘) + Q while Sudoku is active.

If it remains open, press Option (⌥) + Command (⌘) + Esc, select Sudoku, and click Force Quit. Apple — How to force an app to quit on Mac

If Force Quit does not work, restart the iMac using  > Restart.

If the problem continues, identify the exact Sudoku app and verify that its current version is compatible with your iMac's Apple-silicon processor and macOS 27. 

Also check the App Store or the developer's website for a newer version of the app. 

Compatibility should be verified for the specific Sudoku app rather than assumed.

If the app is compatible and fully updated but continues not to close, 

Apple recommends additional troubleshooting, including reinstalling the app if necessary. Apple — If an app on your Mac stops responding, closes unexpectedly, or won't open