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In Progress

Under Consideration for 2022.3.X, 6000.0.X, 6000.1.X, 6000.3.X, 6000.4.X

In Progress in 6000.2.X

Votes

30

Found in

2022.3.67f1

6000.0.56f1

6000.1.8f1

6000.2.0a4

6000.3.0a2

6000.4.0a2

6000.5.0a1

Issue ID

UUM-125778

Regression

Yes

[Metal] Game freezes after command buffer Timeout error

-

Description
CAMetalDisplayLink is causing kIOGPUCommandBufferCallbackErrorTimeout errors. Disabling the CAMetalDisplayLink and using CADisplayLink instead does not cause games to freeze.

WORKAROUND: Disable CAMetalDisplayLink. See https://discussions.unity.com/t/freeze-on-ios-with-metal-display-link/1693201. CAMetalDisplayLink has been disabled by default in some Unity versions: https://issuetracker.unity3d.com/issues/metal-game-freezes-after-command-buffer-timeout-error

Reproduction steps
1. Open a project and build for iOS.
2. Play the game, possibly for more than 30 minutes until the image freezes. A Timeout error is shown in XCode.

Expected behaviour
The game does not freeze.

Actual behavior
The game freezes.

Comments (5)

  1. PandaEngine

    Nov 24, 2025 07:45

    Hi Joao,

    Thanks for your message. We implemented the postprocess build fix, there's no issues so far in our update. I will be following this issue for the final fix.

  2. joao_maia_u3d

    Nov 21, 2025 06:53

    Hi WootWoot,

    As I understand, the iOS 26 drop frame rate issue with CADisplayLink (which is used when CAMetalDisplayLink is disabled) was fixed in iOS 26.1.

  3. joao_maia_u3d

    Nov 21, 2025 06:52

    Hi PandaEngine,

    Please check the updated description of this issue as now it includes a forum post.

    As a workaround, you can disable CAMetalDisplayLink:
    "In your XCode project, go to Classes/UnityAppController.mm. In this function shouldUseMetalDisplayLink change return YES; to return NO;."

    In alternative, you can also update your Unity version to 6000.0.62f1 which comes with CAMetalDisplayLink disabled by default (so you don't need to change it manually).

  4. PandaEngine

    Nov 20, 2025 11:20

    Hi, in our game that runs on Unity 6000.0.58f2 is experiencing freezes that occur randomly. The freeze behaviour is a jitter of two frames back and forth. Underneath, the game is still functional as I can hear UI and game sfx and such. I even tried to change the scene by trying to return to home menu of the game from memory, then an ad showed up, indicating that logic is still working and ad displaying was fine. After I closed the ad, the game was still broken in the same two frame jitter state, image did not change.

    When the device freezes, these errors can be seen when connecting the device to the Console app.

    Execution of the command buffer was aborted due to an error during execution. Ignored (for causing prior/excessive GPU errors) (00000004:kIOGPUCommandBufferCallbackErrorSubmissionsIgnored)

    IOGPUMetalError: <private>

    So far, this issue occured on iPhone 11, 14 Pro, 15 Pro Max. Recently we caught a iPhone 11 test device having this issue, that was freshly upgraded to iOS 26.1.

    Our game is running on Built-in Render Pipeline. Maybe this is a different issue but I could only find this open issue about game freezing related to GPU on iOS devices. It is highly affecting our users of a game with 500k+ DAU.

  5. WootWoot

    Nov 10, 2025 10:28

    Any ETA on that fix ?
    The iOS 26+ drop frame rate is impacting so many users right now.

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