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Fixed in 2018.1.X

Fixed in 2017.1.X, 2017.2.X, 2017.3.X



Found in


Issue ID




[iOS11] 'API called on a background thread: - [UIApplication delegate] > UnityCurrentOrientation' on launch in an empty project



Reproduction steps:
1. Create a new Unity project.
2. Build and run to iOS device.
3. Check the Xcode console:

Main Thread Checker: UI API called on a background thread: -[UIApplication delegate]
PID: 2204, TID: 2872809, Thread name: (none), Queue name: NSOperationQueue 0x1c4039300 (QOS: UNSPECIFIED), QoS: 0
4 ProductName 0x00000001011f5fbc UnityCurrentOrientation + 60
5 ProductName 0x00000001011e3e14 __UnityCoreMotionStart_block_invoke + 108
6 Foundation 0x00000001855ba310 <redacted> + 16
7 Foundation 0x00000001854fa9e4 <redacted> + 72

18 libdispatch.dylib 0x00000001845821c8 <redacted> + 596
19 libdispatch.dylib 0x0000000184581f10 <redacted> + 120
20 libsystem_pthread.dylib 0x000000018481b130 _pthread_wqthread + 1268
21 libsystem_pthread.dylib 0x000000018481ac30 start_wqthread + 4

Reproduced with:
5.6.3p4, 2017.1.2f1, 2017.2.0f2, 2017.3.0b3
iPad Mini 4 iOS 11.0
iPhone 6s iOS 11.0

Not reproducible with:
iPad 5 iOS 10.3.3
iPad Air 2 iOS 9.2

Comments (15)

  1. PixelSquad

    May 07, 2018 08:49

    It's also happening with Unity 5.6. Please do post when fixed.

    It seems that it started happening after we changed the splash screen and orientation settings...

  2. Malachite40

    Mar 17, 2018 08:54

    I have this bug. My code compiles and runs fine - I have yet to release it on the app store. Will in-app purchases work? Or does this bug have to be resolved?

  3. MikePanoff

    Jan 19, 2018 04:03

    This is definitely still in 2017.3. I was able to fix it by disabling Accelerometer which I don't need. I did this in the iOS player settings.

  4. PNordlund

    Jan 18, 2018 09:00

    This is a showstopper. It seems to add 13 extra seconds to game loading time.

  5. MoribitoMT

    Jan 12, 2018 18:29

    I am having this issue with Unity 5.6.4 p4 and XCode 9.2. Game does not crash, but nothing properly displayed in screen.

  6. OldCoderDesign

    Jan 10, 2018 18:05

    You might try setting the Accelerometer Frequency to Disabled in Project Settings->Other Settings, if you do not need the Accelerometer.

    I have four projects all using 2017.2.1.p1. I have three do not have the exceptions on startup while the forth one does. The only difference I found was that the Accelerometer Frequency is set to Disabled for the three projects. So as a test, I set the Accelerometer Frequency to Disabled in the forth project and the exception on startup disappeared. Sadly, for that project I need it set to 60.

    I just did a quick test of 2017.3.0.f0 and the exception on startup does not occur when Accelerometer Frequency is set to Disabled.

  7. Glaswyll

    Jan 09, 2018 22:20

    We are seeing this issue still. Why is it marked fixed?

  8. chuwito

    Jan 04, 2018 02:26

    I still have the same problem in 2017.3.0p1. Does anyone knows a workaround?? Thanks!

  9. kavanavak

    Dec 29, 2017 17:23

    Still there with 2017.3.0f3

  10. mmarsyada

    Dec 07, 2017 06:04

    Anyone know what release fixed this issue?

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