The Surreptitious Aesthetic Override
macOS allows users to customize their visual workspace, including changing the default application icons to custom `.icns` files for a personalized aesthetic. However, a common frustration arises when you painstakingly customize your Dock with custom icons, only to have macOS automatically revert them back to the developer’s default icon. This automatic overriding happens because of the Mac App Store’s background update mechanism. Whenever an application receives an automatic background update, macOS downloads a fresh, complete application bundle, completely overwriting the `.app` file contents, which instantly erases your customized `appicon.icns` file and restores the factory default visual.
Halting the Update Overwrites
To stop macOS from automatically changing your customized app icons back to their defaults, you must restrict the operating system from performing silent background updates on those specific applications.
First, open the App Store application on your Mac. Click on the word App Store in the top menu bar (next to the Apple logo) and select Settings… (or Preferences on older macOS versions). In the settings window, uncheck the box for Automatic Updates. This prevents all App Store apps from silently overriding your icons. However, for apps downloaded outside the App Store (like Chrome or Discord), you must disable their internal update mechanisms individually. Open the specific third-party app, navigate to its internal Settings or Preferences, and look for an “Update” or “About” section. Disable any option labeled “Automatically keep [App Name] up to date” or “Install updates automatically.” By forcing updates to require your manual permission, your custom icons will remain intact until you explicitly choose to run the installer, at which point you will need to re-apply the custom icon once.