"UI unresponsiveness" warning on @main

I'm seeing a runtime warning in Xcode 14 Beta 5 that says "This method should not be called on the main thread as it may lead to UI unresponsiveness."

This is happening on the @main entry point of my app. See below:

The warning shown gives me no insight into what's actually going wrong. I think it may be due to some Core Location code that runs when the app first opens, but is there a way for me to get some more insight into what's causing this?

Or is this possibly an Xcode 14/iOS 16 bug, and this is not an issue to worry about? I'm not getting any warnings on Xcode 13/iOS 15.

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r.token
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  • ">

    —
    Vashbhi

  • Sama here, Xcode 14.2.

    —
    cagli
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Apple Recommended

The purple warning is calling attention to a runtime issue that may impact the performance of your app. In general, you should resolve these issues when they are in your code, by moving the code off the main thread. When you receive one of these runtime performance issues, you can expand the backtrace in the Issue Navigator, available through the View > Navigators > Issues menu, to see where the issue is located.

If you find the issue is pointing at an Apple framework, please use Feedback Assistant to open a bug report to let us know, and include the complete backtrace shown in the issue navigator. You can post the FB numbers to this thread for visibility. Further, if you can't identify where the issue is coming from, as the backtrace points to your main function, please also let us know, including the provided backtrace.

If you find the runtime issue is resulting from an Apple API call used in a sub-optimal way within a third-party library that your app uses, please open a bug report with the library vendor.

Posted by
edford
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  • I've replied back below. please note

    —
    Kim Ju Young

  • I updated to OS 13.0.1 and Xcode to 14.1. My app now reports this same error "This method can cause UI unresponsiveness if invoked on the main thread. Instead, consider waiting for the -locationManagerDidChangeAuthorization: callback and checking authorizationStatus first." and traces it to this bit of code:

    if CLLocationManager.locationServicesEnabled(). So, I implemented the suggested fix, but the complier says that authorizationStatus was deprecated in iOS 14.0

    —
    Herksrule

  • this is not helpful at all

    —
    quinton-ashley
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I get the same warning in XCode14 Beta 5 in my objective C main() when it calls UIApplicationMain(argc, argv, nil, nil); (See below)

I use a WKWebView to allow user to login.

For me it seems to happen if I display a WkWebView when I start my Aop. If I run and don't need to display the WkWebView (Ie I already have login details) then I don't seem to get the warning...

int main(int argc, char *argv[]) {

    @autoreleasepool {

        int retVal = UIApplicationMain(argc, argv, nil, nil);

        return retVal;

    }

}

All a bit worrying but I have no clue what it means.

Posted by
davemaj
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Happening to me too. Someone please solve this

Posted by
LukeDev95
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I also encountered the same phenomenon.

However, depending on the loading URL, this message may or may not be displayed.

I'm not quite sure what the difference is.

When this message was not displayed, the following message was displayed.

Could not signal service com.apple.WebKit.WebContent: 113: Could not find specified service

Xcode Version 14.0 beta 6 (14A5294g)

iOS16.0 beta 8

iPhone SE 2generation

Posted by
mario25
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  • I'm seeing the same think in WKWebView, every time I show WKWebView it prints out the following error message multiple times: "This method should not be called on the main thread as it may lead to UI unresponsiveness."

    I also see that navigation to different web pages in WKWebView seems to lag a bit, like something is blocking the main thread. Haven't been able to figure out the cause yet.

    Anyone have any insight?

    —
    ov_xanderbuck

  • system console log: [pageProxyID=69, webPageID=70, PID=1923] WebPageProxy::didCommitLoadForFrame: frameID=3, isMainFrame=1 This method should not be called on the main thread as it may lead to UI unresponsiveness.

    When the app uses wkwebview to load a webpage for the first time, Web content displays only half the screen, It looks like the wkwebview is hang. Then all pages using wkwebview will have the above situation.

    —
    hellboys

  • Same here! iOS16 release, WKWeb content could not be displayed or half screened

    —
    kevin_z
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Any solutions on this? Someone please solve this.

Xcode 14 Beta 5 iOS 16.0

Posted by
mmm34
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Same here!

Posted by
imufun
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Same here on Xcode 14 beta 6 / iOS 16.0 beta 8. Would love to know if any updates.

Posted by
zhang13
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same for me a warning error : This method should not be called on the main thread as it may lead to UI unresponsiveness.

Posted by
Nidhal_Eagle
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I'm experiencing the same thing with WkWebView (not in SwiftUI).

Xcode 14.0 beta 6 (14A5294g)

Posted by
s.singh
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  • Following up on my original post.. I updated to Xcode 14 RC but I'm still seeing the same issue: "This method should not be called on the main thread as it may lead to UI unresponsiveness" warning.

    I believe it is happening when WkWebView.load(URLRequest) is called. If I comment out the particular load() call, the warning isn't displayed.

    —
    s.singh
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Same here with UIKit, AppDelegate and WKWebView. Points to class AppDelegate in the warning... no other information.

Posted by
jorydekort
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If you are continuing to see this when using Xcode 14 Release Candidate running an app on iOS 16 Release Candidate, please provide detailed specifics in a bug report., and then post the FB number here.

Posted by
edford
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It was the same on iOS16RC&xcode14RC. Posted: FB 11480364

Posted by
no.mo.r.r.
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Yep WkWebView.load(URLRequest) in a UIKit app causes this issue for me in the Xcode 14 RC.

Posted by
itsyusuf
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  • I have the same problem with the code. Xcode ver. 14.2

    —
    zmnbgd
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Same error using Xcode Version 14.0 (14A309), iOS16 on iPad. Using WkWebView with SwiftUI.

Posted by
zeser78
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Same error for me happening

Posted by
mqaiserbutt
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Facing the same issue, any solution or workaround?

Posted by
vito_yang
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  • Same issue on the AppDelegate

    —
    DannyByersII

  • exactly the same...

    —
    kaizei

  • Same issue... but the app works fine...

    —
    Edutgn75
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