Game Center SignIn alert appears on macOS 26 (Tahoe) without capability or entitlement

Hello,

On macOS 26 (Tahoe), when building a OSX app that includes GameKit code, calling GKLocalPlayer.local.authenticateHandler shows the "Sign In to Game Center" alert (e.g. didShowFullscreenSignIn) — even if the app does not have the Game Center capability enabled or any related entitlement (com.apple.developer.game-center).

This alert only appears when the user is not signed in to Game Center in system settings.

However, when testing the same code path on iOS app built with macOS 26 (Tahoe), the alert does not appear unless the proper capability and entitlement are included.

This behavior is different from macOS 15 (Sequoia) + Xcode 15.x. Prior to the update, Game Center features did not work at all even with the OSX app without Capability and Entitlements.

Steps to Reproduce

  1. Create a new OSX app target (App Sandbox enabled, no Game Center capability).
  2. Add minimal GameKit code:
GKLocalPlayer.local.authenticateHandler = { _, _, _ in }
  1. Build OSX app and run on macOS 26 (Tahoe).
  2. Ensure Game Center is signed out in System Settings.
  3. Observe: “Sign In to Game Center” alert appears automatically.

Expected Behavior

  • When Game Center capability and entitlement are not present, authenticateHandler should fail silently, and no signIn alert should appear.

Actual Behavior

  • On OSX app, the Game Center signIn UI appears even without any Game Center capability or entitlement.
  • On iOS app, this alert does not appear.
  • *Build Configuration: built with the same condition. (macOS 26 + Xcode 26)

Question

Could you please confirm whether this behavior is an intentional change in macOS 26 or a bug only for OSX apps in the GameKit authentication flow?

Thank you.

Answered by DTS Engineer in 861969022

Hello,

Given what you've described this appears to be a regression (unexpected change in behavior), particularly with the difference in behavior between macOS and iOS.

Please send us a bug report with the information above. A sample Xcode project that shows the issue would also be helpful.

Hello,

Given what you've described this appears to be a regression (unexpected change in behavior), particularly with the difference in behavior between macOS and iOS.

Please send us a bug report with the information above. A sample Xcode project that shows the issue would also be helpful.

Game Center SignIn alert appears on macOS 26 (Tahoe) without capability or entitlement
 
 
Q