UAR + Unity + iOS Face tracking crashing consistently


Using the UAR 3.0.1 plugin and Unity 2020.3.9f1 on an iPhone 8 Plus running iOS 15.3.1 crashes running the face tracking example for both Standard Rendering Pipeline and Universal Rendering Pipeline after running for about 15-30 seconds.

Also tested on a 2019 iPad Pro running iOS 14.4.2 and same outcome occurred with a crash 15-30s after the app started.

The face tracking does work, the ZCV.Bundle is set in the Xcode project and the face tracking works. Also to note is the camera feed is much darker when running the Zappar Unity App compared to the image from the actual camera.



would it be possible for you share some application logs for us to inspect? To view Debug.Log output along with system logs you may use the following steps:

  • In Unity, build to iOS with Development Build selected in Build Settings
  • Open the project in XCode. It is assumed here that you have a Provisioning Profile configured.
  • Build and run the app on the device
  • Open the console output window (View/Debug Area/Activate Console
  • In addition to the System output messages, you will also see your Debug.Log output here.
  • You can use the Filter option at the bottom of this window to limit the text output
  • Copy the output and paste into a text editor


@Shubham Here is the console log. There is no Debug.Logs as this is just the UAR face tracking sample scene in isolation.

2022-02-23 18:12:24.680309+0000 Zappar3[743:134541] Built from ‘2020.3/staging’ branch, Version ‘2020.3.9f1 (108be757e447)’, Build type ‘Release’, Scripting Backend 'il2cpp’

2022-02-23 18:12:24.681608+0000 Zappar3[743:134541] MemoryManager: Using ‘Default’ Allocator.

→ applicationDidFinishLaunching()

→ applicationDidBecomeActive()

GfxDevice: creating device client; threaded=1

Initializing Metal device caps: Apple A11 GPU

Initialize engine version: 2020.3.9f1 (108be757e447)

2022-02-23 18:12:25.616767+0000 Zappar3[743:134541] Unbalanced calls to begin/end appearance transitions for <UnityViewControllerStoryboard: 0x11a0541d0>.

2022-02-23 18:12:25.617168+0000 Zappar3[743:134541] Unbalanced calls to begin/end appearance transitions for <UnityDefaultViewController: 0x11a053540>.

UnloadTime: 4.468250 ms

2022-02-23 18:12:28.016507+0000 Zappar3[743:134541] WARNING: -[<AVCaptureVideoDataOutput: 0x811bb060> setMinFrameDuration:] is deprecated. Please use AVCaptureDevice setActiveVideoMinFrameDuration

2022-02-23 18:12:28.639628+0000 Zappar3[743:134541] Started camera for device

2022-02-23 18:12:28.644539+0000 Zappar3[743:134541] DID GET RESPONSE 403

2022-02-23 18:12:28.648791+0000 Zappar3[743:134541] DID COMPLETE NO ERROR

UNLICENSED! Please register this app’s identity (com.DefaultCompany.Zappar3) at

To note there is no error when the app freezes up. I get the popup about registering the identity too zappar then leave the tracking that works for about 30s after that. No more messages are posted in the log as there’s nothing going on. Then the app freezes and no log is posted for why the freeze is happening.

Its also to not the the camera feed is much darker than what the iPhone camera app displays as if the Gamma levels are not correct when running the Unity app but this is a separate issue entirely.

Kind regards,


It seems you haven’t registered the projects’ bundle identifier with us. To fix this, simply head over to distribution hub ( and add a new license for your preferred platform. In this case, select Type as iOS and Hostname to match your bundle identifier and create a new license.

Regarding the camera feed, can you confirm the color space under project settings. We expect this to be set as ‘Gamma’ which is default on Unity. In case it is set to Linear can you change it? Otherwise, please provide some reference images for comparison here.