I am also with the same problem with no solution. 

I, too, am affected, and this is coming at a time-critical moment when my company is trying to get an app (iOS 11.3, Vuforia 6.5, Unity 2017.3) out the door. It's a bit underwhelming how Vuforia support has handled addressing this issue or releasing updates regarding it.

I also have the black screen issue for iOS 11.3 (using Unity 2017.3, Vuforia and model target detection)

The issue only occurred when I upgraded my iPad from iOS 11.2.1 to 11.3. This also required an upgrade of xCode to compile and run on the new iOS.

I have the same problem. It appeared when I updated my iOS to 11.3, I have a Xcode 9.3 and ios sdk 11.3 (not Unity)

Please tell me how to fix this error.

Hello all,

I am working to get information about the plan for resolving this issue. I will update the forums as soon as I have any relevant information.

Thanks for your patience,

Vuforia Support

Seriously! the issue is known since February 5 and you still have no solution while the OS is already out? We have an ongoing project that needs to be distributed on ios and we are planning to subscribe to a license but we are going to abandon vuforia and work with ARKit instead.

Since we already have given our bucks for a commercial license, I thought should give my 2cents here.

You really to need this fixed soon. It already should have been fixed before the official iOS 11.3 and XCode 9.3.

Knowing Apple and the surrounding ecosystem it must be clear to you, that using an "outdated" versions is nothing most serious Apple developer are willing to do. Mostly  since Apple has a tendency of forcing new stuff onto developers.

So again, get this fixed.

Thanks

Hi,

I'm adding my "not so happy Vuforia developer" post here. We were considering buy the Vuforia commercial licence but during development we get stucked on iOS 11.3 because of this issue. I don't know why there's no update about this since 2 month since the OS version is now out, and our target device is now stuck in 11.3. Not any workaround or a hotfix.

We started to work on our own solution for AR in iOS, and we are delaying the licence buy because of this, maybe if we go Android someday. For iOS it really down our confidence over Vuforia support capacity, because if someday there's another major issue, we don't want to be stuck for another 2 month. And since the code source of Vuforia is almost completly locked, we can't get it fix ourselves.

Hope you'll find a quick fix, and good luck :)

Hello all,

We will be providing a patch for Vuforia 7.1 that will address this issue. We are actively working on getting this patch out the door and I will provide additional updates with exact timing in the near future.

With ARKit 1.5 beta, we found early on that Apple significantly broke our integration. However, due to the known timing of our 7.1 release and the unknown timing of iOS 11.3, we (blindly) moved forward with fixing the issue in our 7.2 release. Now that iOS 11.3 has officially release, we have escalated the need for a patch and it is currently underway.

Why not a patch for 7.0? With 7.0 SDK, Vuforia's direct integration with Unity also means we are dependent upon them for distributing patch releases. Our experience (so far) is that Unity has been slow to release patches for 2017.3. With Vuforia 7.1 (Unity 2018.1), we have created an installer function that decouples this Unity dependency and allows us to provide out-of-band patch releases.

Apologies that we do not have a 'quick fix,' but we are working towards getting the patch release out.

This user over on the Unity forums claims to have found a way to work around this issue if any of you would like to give that a try: https://forum.unity.com/threads/known-issue-when-developing-with-vuforia-7-xcode-9-3-and-ios-11-3-beta-arkit-1-5.516117/#post-3450395

Thanks,

Vuforia Support

Hi,

Thank you for your answer, it would be great if Vuforia can be updated without Unity.

Because not all project needs to keep Unity up to date, most of the time, we lock a version when we reach a critical milestone of the project. So if an issue like this happens and you have to upgrade Unity in a project that is already Silver, you are in some deep shiat :) Can you maybe get you include in their new "Package Manager" system (which seems to allow package to update themselves regardless of the Unity version) ? Or are you going to release patches on your website ?

I hope for a quick fix but it's good to know that this issue is finally getting the priority it needs.

Have a great day and thanks for your work

We are still seeing this problem using Unity 2017.3.0f3, Xcode 9, ios 11.3 (we are testing on an iphone 8) and Vuforia SDK v7.1.31. App and menu startup correctly but when the main scene with the AR camera and image targets is loaded the screen remains black and trackers are not tracked (UI is shown). The same project works for android phones and tablets.

Any workaround or fixes for this?

Thanks

BenouKat wrote:

Hi,

Thank you for your answer, it would be great if Vuforia can be updated without Unity.

Because not all project needs to keep Unity up to date, most of the time, we lock a version when we reach a critical milestone of the project. So if an issue like this happens and you have to upgrade Unity in a project that is already Silver, you are in some deep shiat :) Can you maybe get you include in their new "Package Manager" system (which seems to allow package to update themselves regardless of the Unity version) ? Or are you going to release patches on your website ?

I hope for a quick fix but it's good to know that this issue is finally getting the priority it needs.

Have a great day and thanks for your work

This is essentially the plan starting with Unity 2018.1 + Vuforia 7.1 moving forward. We understand the tight coupling currently present causes issues such as the one you describe here and we are hoping the new approach will alleviate that.

Thanks,

Vuforia Support

What's the timeline release ETA for 7.2 

Does anyone have a verified hot-fix for the black screen on 11.3 devices? I’ve been running into this issue since beta. I wasn’t expecting this to remain ongoing post public release. 

ERROR/AR(5870) 2018-03-03 16:25:14: CameraDevice::getCameraCalibration(): Failed to get camera calibration because the camera is not initialized.

Logs: Start of log to <Start> of Vuforia, no running logs.

2018-03-02 16:25:08.273314-0700 ProductName[5870:1821460] [DYMTLInitPlatform] platform initialization successful

2018-03-02 16:25:08.374353-0700 ProductName[5870:1821259] -> registered mono modules 0x102373400

-> applicationDidFinishLaunching()

2018-03-02 16:25:09.733814-0700 ProductName[5870:1821259] Metal GPU Frame Capture Enabled

2018-03-02 16:25:09.734994-0700 ProductName[5870:1821259] Metal API Validation Disabled

-> applicationDidBecomeActive()

GfxDevice: creating device client; threaded=1

Initializing Metal device caps: Apple A11 GPU

Initialize engine version: 2017.3.1f1 (fc1d3344e6ea)

WARNING: Shader Unsupported: 'Hidden/BlitToDepth' - Pass '' has no vertex shader

WARNING: Shader Unsupported: 'Hidden/BlitToDepth' - Setting to default shader.

WARNING: Shader Unsupported: 'Hidden/BlitToDepth_MSAA' - Pass '' has no vertex shader

WARNING: Shader Unsupported: 'Hidden/BlitToDepth_MSAA' - Setting to default shader.

Setting up 1 worker threads for Enlighten.

  Thread -> id: 170a37000 -> priority: 1

UnloadTime: 4.606125 ms

Compiled for iOS

Vuforia.PlatformRuntimeInitialization:InitPlatform()



(Filename: /Users/builduser/buildslave/unity/build/artifacts/generated/common/runtime/DebugBindings.gen.cpp Line: 51)

Initializing Vuforia...

2018-03-02 16:25:14.473598-0700 ProductName[5870:1821259] [MC] System group container for systemgroup.com.apple.configurationprofiles path is /private/var/containers/Shared/SystemGroup/systemgroup.com.apple.configurationprofiles

2018-03-02 16:25:14.475048-0700 ProductName[5870:1821259] [MC] Reading from public effective user settings.

INFO/AR(5870) 2018-03-03 16:25:14: Vuforia selected rendering API Metal

INFO/AR(5870) 2018-03-03 16:25:14: Vuforia SDK version 7.0.47

INFO/AR(5870) 2018-03-03 16:25:14: Detected and enabled use of Apple ARKit

2018-03-02 16:25:14.533857-0700 ProductName[5870:1821259] Rendering mode set to: Metal

2018-03-02 16:25:14.561323-0700 ProductName[5870:1821259] Rendering mode set to: Metal

Vuforia initialization successful

Vuforia.VuforiaRuntime:InitVuforia()



(Filename: /Users/builduser/buildslave/unity/build/artifacts/generated/common/runtime/DebugBindings.gen.cpp Line: 51)

Name: VuforiaSizzle

AudioTracks: 1

Frames: 2483

FPS: 29.9700298309326

Height: 1080

Width: 1920

Length: 82.8494337178554

Path: /Users/Truman/Unity/Udemy-AR-2/Assets/SamplesResources/SceneAssets/ImageTargets/Video/VuforiaSizzle.mp4

VideoController:LogClipInfo()



(Filename: /Users/builduser/buildslave/unity/build/artifacts/generated/common/runtime/DebugBindings.gen.cpp Line: 51)

Pause Video

VideoController:Pause()

VideoTrackableEventHandler:OnTrackingLost()



(Filename: /Users/builduser/buildslave/unity/build/artifacts/generated/common/runtime/DebugBindings.gen.cpp Line: 51)

ERROR/AR(5870) 2018-03-03 16:25:14: CameraDevice::getCameraCalibration(): Failed to get camera calibration because the camera is not initialized.

INFO/AR(5870) 2018-03-03 16:25:14: ObjectTracker: Successfully created dataset

Successfully created data set.

2018-03-02 16:25:14.684126-0700 ProductName[5870:1821259] JPEGDecompressSurface : Picture decode failed: e00002c2

2018-03-02 16:25:14.684156-0700 ProductName[5870:1821259] [] <-<<< FigPhotoJPEGDecoder >>>-> _createPixelBufferFromJPEG: OSStatus _createPixelBufferFromJPEG(CFDataRef, CFDictionaryRef, _Bool, _Bool, int *, FigPhotoSize *, IOSurfaceRef, CVPixelBufferRef *, _Bool), JPEG DECODE FAILED

2018-03-02 16:25:14.686424-0700 ProductName[5870:1821259] JPEGDecompressSurface : Picture decode failed: e00002c2

2018-03-02 16:25:14.686439-0700 ProductName[5870:1821259] [] <-<<< FigPhotoJPEGDecoder >>>-> _createPixelBufferFromJPEG: OSStatus _createPixelBufferFromJPEG(CFDataRef, CFDictionaryRef, _Bool, _Bool, int *, FigPhotoSize *, IOSurfaceRef, CVPixelBufferRef *, _Bool), JPEG DECODE FAILED

Found Trackable named 27days--EPArtwork with id 1

Vuforia.StateManager:AssociateTrackableBehavioursForDataSet(DataSet)

Vuforia.DataSet:Load(String, StorageType)

Vuforia.DatabaseLoadARController:LoadDatasets()

Vuforia.VuforiaARController:Start()

System.Reflection.MonoMethod:Invoke(Object, BindingFlags, Binder, Object[], CultureInfo)

Vuforia.DelegateHelper:InvokeDelegate(Delegate, Object[])



(Filename: /Users/builduser/buildslave/unity/build/artifacts/generated/common/runtime/DebugBindings.gen.cpp Line: 51)

StartVuforia

Hi everyone, do we have any update from this issue?

Is there any progress with this issue?

I am also having this issue which is extremely frustrating as I am ready to ship an update to my iOS app. Vuforia charges (in my opinion) quite a high price for a commercial licence. The fact that their SDK doesn't work with a current version of iOS is simply unacceptable. 

With that out of the way can someone please tell me if there is anything I can do to fix this, here is my setup :

• Unity 2017.3.0p3
• Vuforia 7.1.31
• I have removed the unity ARKit package contents from my project
• Xcode 9.3

Using vuforia arcamera and image targets results in a black screen

Same here....

Waiting for solution... my clients can't use the app with Iphones with IOS 11.3

please, let us know when approximately vuforia 7.1 with  the bug fixed is going to be released!

Thank you

Same here...

I'm getting complaints from some users who have downloaded the app from the App Store, who are experiencing this black screen when the camera is activated. I was hunting to find out why this was happening, and came across this thread!

I can recreate the issue on one of my devices (iPhone 6S Plus with iOS 11.3), but my iPad 2 (again with 11.3) seems to work fine, as do all the Android devices I've tested.

Be good to get a solution soon!

Same problem here.

When will be available Vuforia 7.2 with this issue fixed?

fabiotg54 wrote:

Same problem here.

When will be available Vuforia 7.2 with this issue fixed?

For developers of vuforia if it can be useful I have solved using sdk release 6 instead of 7

My iPhone auto-updated to 11.3 last night. 

And now I live in darkness. 

Please send help. Make sure they bring a flashlight.

Patiently waiting for 7.2, in the dark.

-Chilton

Same problem here and having to upload a customer app right now, so no time to wait for an update...

But as mentioned by a Vuforia support team member, this solution is working: https://forum.unity.com/threads/known-issue-when-developing-with-vuforia-7-xcode-9-3-and-ios-11-3-beta-arkit-1-5.516117/#post-3450395.

To recap:

1. Download Xcode 9.2 (https://developer.apple.com/download/more/)

2. Copy /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport/11.3 (15E217) to your new (old) Xcode 9.2, for exemple: /Applications/Xcode\ 9.2/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport.

3. Rename 11.3 (15E217) to 11.3, and 11.2 (xxx) to 11.2 in your Xcode 9.2 DeviceSupport folder.

4. Build your unity project.

5. Open your project with Xcode 9.2. You can now build for your iOS 11.3 iPad without having this black screen.

Best.

Here's a video walkthrough for anyone having this issue.

https://www.youtube.com/watch?v=3roMSonIG5c

-Chilton

Thank you, Fixed the black screen issue ;)

Hello Strasza.

What im getting from your post that for Unity 2017.3/4 Vuforia 7.0.x there will no quick way to fix the issue.

Is it planed to bring out Vuforia 7.0.x for 2017.4 ? A long term supported version that will not be able to get quick fixes... is not a good option.

Hello Straza,

any news about the fix? It's been a long time since the issue is known and Xcode 9.3 + iOS 11.3 are officially launched. I agree with the user above that commented on how Apple ecosystem quickly adapts to newer versions. Our product is complex and requires integration with a lot of swift native code and this problem is holding us back on our migration to Xcode 9.3.

To be honest since Vuforia started to ship together with Unity it has been a nightmare for us. I understand that it makes things easier to starting developers, but remember that there is also the problem with the auto-attach camera script that you haven't patched yet and the haunting sample files that are copied into my project every single time!

Please, revert to the old way: Vuforia as a separate plugin and no automatic configurations/attachments and integration code open so we can work around problems like this asap!

Best regards,

thank you " forum" for resolving this problem while waiting for an update of vuforia !

Best regards

Squallow

Hello all,

This issue has been resolved within Vuforia 7.1.34.

The native SDK containing this fix can be downloaded here: https://developer.vuforia.com/downloads/sdk

Unity 2018.1.0f1 and later will be able to download this version of the SDK. This commercial build of 2018.1 should be available very soon.

Thank you all for your patience as we resolved this issue,

Vuforia Support

I have just tested it today and I still got the black screen on my iPad Pro 2017.

I have Xcode 9.3 and devices with iOS 11.3.

I have just tested with Unity 2018.1.0b13 and Unity 2018.2.0b1 and I still got the black screen. Instead of Vuforia 7.1.34., they actually downloaded 7.1.31:a1fa87164815f507ad260aae34217617 (direct copied form the "version" text file in Asset folder).

iOS 11.3.1 is out officially. Has anyone tested it on that yet? Or is it working with thee Vuforia update? I tried all the methods here but only one by chilton works. Has anyone tried 11.3.1 yet?

Tried it with iOS 11.3.1.  Still the black screen. :(

vincentchan wrote:

I have just tested it today and I still got the black screen on my iPad Pro 2017.

I have Xcode 9.3 and devices with iOS 11.3.

I have just tested with Unity 2018.1.0b13 and Unity 2018.2.0b1 and I still got the black screen. Instead of Vuforia 7.1.34., they actually downloaded 7.1.31:a1fa87164815f507ad260aae34217617 (direct copied form the "version" text file in Asset folder).

You'll need Vuforia 7.1.34 for the fix for this issue. Unity 2018.1.0f1 or later (the commercial release) will have the download option for this. You can get it to work with 2018.2, but due to this version being integrated with the Unity Hub, you'll need a couple extra steps. The user Aidan-Wolf describes how to update Vuforia within the Unity Hub 2018.2 build in this thread: https://forum.unity.com/threads/known-issue-when-developing-with-vuforia-7-xcode-9-3-and-ios-11-3-beta-arkit-1-5.516117/

Thanks,

Vuforia Support

Is it possible to use Vuforia 7.1.34 with Unity 2017.3.1? If so, how to we do that? :)

Thanks

Chilton method worked - copy iOS 11.3 device support file from Xcode 9.3 into Xcode 9.2 - Compile build with Xcode 9.2.

Installing directly onto iPhone running 11.3 worked.

Question - I'm submitting archive from this build to the app store via Xcode 9.2. Will this work on iPhones running 11.3?

Vuforia Management - This is a critical problem that seems like it should be getting major resources to patch immediately.

The following setup worked for me:

• Unity 2018.1.0f1
• Vuforia 7.1.34
• XCode 9.3

Tested on:

• iPhone 6 running iOS 11.3
• iPad pro 9.7" running both iOS 11.3 and iOS 11.3.1

No luck here.. I tried it with the latest Vuforia (7.1.34) and the latest iOS (11.3.1) on iPhone 7. I don't use Unity, and tried it with 3 XCode versions: 9.2 (with the workaround for 11.3), 9.3 and 9.4 (beta). All with the same results.. the black screen

edulink wrote:

No luck here.. I tried it with the latest Vuforia (7.1.34) and the latest iOS (11.3.1) on iPhone 7. I don't use Unity, and tried it with 3 XCode versions: 9.2 (with the workaround for 11.3), 9.3 and 9.4 (beta). All with the same results.. the black screen

Same result here but after using the exact same of the unity editor 2018.1.0f2 and updating the vuforia plugin within to the patch version 7.1.34, we are still experiencing the black screen issue with xcode 9.3 AND xcode 9.2.. not good news.. rolling back to 2018.1.0f1 for now to see if it fixes... if not we will have to roll back to an older version of unity? This is not ideal for us 

ICEDevelopers - Can you confirm that the Vuforia version in your Vuforia Configuration is 7.1.34? Could you also share the logs when the issue is occurring?

edulink - Can you also share your logs?

Thanks,

Vuforia Support

Strasza wrote:

ICEDevelopers - Can you confirm that the Vuforia version in your Vuforia Configuration is 7.1.34? Could you also share the logs when the issue is occurring?

edulink - Can you also share your logs?

Thanks,

Vuforia Support

I can confirm we are using 7.1.34, xcode 9.3 and unity 2018.1.0f1 - After spending all day yesterday looking at the Xcode logs and removing things from the unity scene, the main cause of our issue is the UI Canvas component in Unity. Project works fine without a Canvas in the Unity Scene - as soon as we add one, the Vuforia camera renders black and the below Xcode log shows

I must stress that this issue appears to be specific to our Ipad Air models running IOS 11.3, our Ipad Pro and iPhone models on 11.3 run the app with no problems - using an iphone 6s, iphone 7 and iphone x.

Scroll to the bottom of the log to see the UIView conflicts

Xcode Log:

StartVuforia

UnityEngine.DebugLogHandler:Internal_Log(LogType, String, Object)

UnityEngine.DebugLogHandler:LogFormat(LogType, Object, String, Object[])

UnityEngine.Logger:Log(LogType, Object)

UnityEngine.Debug:Log(Object)

Vuforia.VuforiaARController:StartVuforia(Boolean)

Vuforia.VuforiaARController:StartAfterInitializationCompleted()

Vuforia.VuforiaARController:UpdateState(Boolean, Boolean)

Vuforia.DigitalEyewearARController:Update()

System.Reflection.MonoMethod:InternalInvoke(Object, Object[], Exception&)

System.Reflection.MonoMethod:Invoke(Object, BindingFlags, Binder, Object[], CultureInfo)

System.Reflection.MethodBase:Invoke(Object, Object[])

System.Delegate:DynamicInvokeImpl(Object[])

System.MulticastDelegate:DynamicInvokeImpl(Object[])

System.Delegate:DynamicInvoke(Object[])

Vuforia.DelegateHelper:InvokeDelegate(Delegate, Object[])

Vuforia.DelegateHelper:InvokeWithExceptionHandling(Action)

Vuforia.VuforiaBehaviour:Update()



(Filename: /Users/builduser/buildslave/unity/build/Runtime/Export/Debug.bindings.h Line: 43)

cameraDeviceStartCamera

2018-05-11 08:53:49.516802+0100 demo[283:9907] ERROR/AR(283) 2018-05-12 08:53:49: VideoBackgroundConfig with screen size of zero received, skipping config step

2018-05-11 08:53:49.523841+0100 demo[283:10000] Deleting old image data @ 0x0

2018-05-11 08:53:49.523956+0100 demo[283:10000] Created new image data buffer @ 0x11b4a8000 w/ 1382400 bytes

Setting up 1 worker threads for Enlighten.

  Thread -> id: 17174f000 -> priority: 1

2018-05-11 08:53:50.404819+0100 demo[283:10028] DEBUG/AR(283) UIView has CAMetalLayer layer class

2018-05-11 08:53:50.405214+0100 demo[283:10028] DEBUG/AR(283) UIView does not respond to selector renderFrameVuforia

2018-05-11 08:53:50.405349+0100 demo[283:10028] DEBUG/AR(283) UIView has CAMetalLayer layer class

2018-05-11 08:53:50.405389+0100 demo[283:10028] DEBUG/AR(283) UIView does not respond to selector renderFrameVuforia

2018-05-11 08:53:50.405422+0100 demo[283:10028] DEBUG/AR(283) Could not find a UIView with CAEAGLLayer or CAMetalLayer layer class that responds to selector renderFrameVuforia

Hey Guys, Could you solve this problem???

If you did... Can you tell us how? Thank you so much!!

NivekJump wrote:

Hey Guys, Could you solve this problem???

If you did... Can you tell us how? Thank you so much!!

As mentioned on other threads in this forum - if you are using Unity, go to player settings:



Change the graphics API from Metal (or automatic) to GLES 3.0 or GLES 2.0 to fix this issue in unity.



You're welcome ;)

Didn't solve the problem. Still getting a black screen. Tried OpenGLES2 and or OpenGLES3. 

 

So I've been able to get my app working once I went with the Xcode 9.2 hack for 11.1 and forward. Problem I'm having now is that the app will work for a day or 2 but then it will kinda crash on startup. Kinda crash meaning it will return to the homescreen after a frame of black but I will notice that it's working/rendering when I double click home and see the preview with my UI and camera feed. But I can't switch to it as it will soft crash again to the background. Anyone else notice anything like this lately? 

Same problem here. Urgently need a fix!

pixelstein wrote:

Didn't solve the problem. Still getting a black screen. Tried OpenGLES2 and or OpenGLES3. 

 

What device are you using? Also, what elements are in your scene - is there a Unity UI Canvas?

Black screen in ipad pro xcode 9.5 vuforia 7.....some additional elements:

I deployed the application with xcode 9.5 and cable to ipad pro.....all was ok.....after some days the app started reporting the problem. i used test flight to deploy the app, i reinstalled from test flight several times.....nothing worked. Now ipad has ios 11.3.1 (when app worked fine ipad was ios 11.3 now 11.3.1)

Need solution soon please 

Vuforia TEAm! PLEASE give us a feedback.....do you know this issue?

I checked and what happened is that there is no reason why camera stop working the model is IPAD Pro with a10x processor in other ios devices it works

it's urgent my client is waiting for a response

Hello pant76,

It is recommended to use XCode 9.3 as that is the latest release and later versions are in beta and un-tested. Without further information on the issue you are having there is not much for us to do to assist. Can you share any relevant log data from your issue? Are you able to reproduce this within the samples? Are you on Unity or native? Which version of Unity and Vuforia?

Thanks,

Vuforia Support

Strasza wrote:

Hello pant76,

It is recommended to use XCode 9.3 as that is the latest release and later versions are in beta and un-tested. Without further information on the issue you are having there is not much for us to do to assist. Can you share any relevant log data from your issue? Are you able to reproduce this within the samples? Are you on Unity or native? Which version of Unity and Vuforia?

Thanks,

Vuforia Support

Hi, thanks for reply

Xcode v.9.3

Unity3d V. 2017.3.0p3 with Vuforia 7.0.43

Ipad Pro processor A10x IOS 11.3.1

The xcode log is attached.

I also tryed in the same situation with iphone6 IOS 11.3.1 and all is ok there.....you can find also log iphone in attachment

PLEASE NOTICE:

I bought the ipad, connected it and installed my app on device.....everithyng worked ok for about 3/4 days..... then the black screen problem appeared (same application....no redeploy).....maybe (not sure) ipad was upgraded from IOS 11.3.0 to 11.3.1

SAME problem with Vuforia samples imagetargets -->the log attached is comung from vuforia sample not my app

NOTICE:

today i factory-resetted ipad (now ios 11.3.1) and reinstalled vuforia samples....

Black screen with rear camera.....all ok with front camera