Xcode 26 - Crashing Loading Custom TabBarViewController

Question

Created 1w

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When I build my app for iPad OS, either 26, or 18.5, as well as iOS on 16.5 from Xcode 26 with UIDesignRequiresCompatibility enabled my app is crashing as it loads the main UIViewController, a subclassed UITabBarController which is being loaded programatically from a Storyboard from another SplashScreen ViewController.

On i(Pad)OS 18.5 I get this error:

Thread 1: "Could not instantiate class named _TtGC5UIKit17UICoreHostingViewVCS_21ToolbarVisualProvider8RootView_ because no class named _TtGC5UIKit17UICoreHostingViewVCS_21ToolbarVisualProvider8RootView_ was found; the class needs to be defined in source code or linked in from a library (ensure the class is part of the correct target)"

On iPadOS 26 I get this error:

UIKitCore/UICoreHostingView.swift:54: Fatal error: init(coder:) has not been implemented

There is no issue building from Xcode 16.4, regardless of targeted i(Pad)OS.

Answered by Frameworks Engineer in 842737022

Please file a feedback report, this is a bug in UIKit.

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Answer 1

Frameworks Engineer OP

Apple

1w

Accepted Answer

Please file a feedback report, this is a bug in UIKit.

0

Answer 2

bjhomer OP

1w

I am also running into this. I filed FB17990409, which contains a simple sample app that reproduces the issue.

It appears that having an NSToolbar in an Xcode26-compiled storyboard is enough to trigger the crash when running on iOS 18. So a workaround for now might be to install your toolbars in code.

1