Exception unarchiving UIToolbar in iOS 18.5 simulator with Xcode 26 beta 2

Question

Created 2w

Replies 7

Boosts 2

Participants 5

I'm running into a persistent problem with the iOS 18.5 simulator in Xcode 26 beta 2. I have built a very simple test app with a storyboard that includes only a toolbar added to the ViewController scene in the storyboard. The test app runs fine in iOS 26 simulators.When I try to run it in the iOS 18.5 simulator for iPhone Pro or iPad (16), it fails while unarchiving the storyboard (as far as I can tell) with this error message in the Xcode console:

*** Terminating app due to uncaught exception 'NSInvalidUnarchiveOperationException', reason: '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)' terminating due to uncaught exception of type NSException CoreSimulator 1043 - Device: iPad (A16) (3E70E25F-8434-4541-960D-1B58EB4037F3) - Runtime: iOS 18.5 (22F77) - DeviceType: iPad (A16)

I'd love a simple workaround for this.

Boost

Answer 1

DTS Engineer OP

Apple

2w

Please file a feedback report, this is a bug in UIKit. Post the Feedback ID here once you do.

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Answer 2

dsbirch OP

2w

FB18587743

(Slightly misleadingly titled as a crash.)

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Answer 3

dsbirch OP

2w

Now that I've tried my full project on my iPad, I can see that it's happening there as well. It continues to run just fine from Xcode 16.4.

I updated the feedback with the Console message from Xcode 26.

1

Answer 4

javierCantoAltomobile OP

1w

Happening to me as well on Xcode 26 Beta 3 and simulator with iOS 18.3.1. It also occurs on real devices with iOS 18.

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Answer 5

dsbirch OP

1w

Like javierCantoAltomobile, I am also seeing this on device. In my case it's on an iPad running iOS 18.5.

Here’s what’s logged in the Xcode 26 beta 3 console while trying to run the project (and then printing the Exception):

Toolbar-Exception(907,0x1fa87db40) malloc: xxm: failed to initialize deferred reclamation buffer [2] (null)
Printing description of exception->exception:
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)
(null)

I sure hope this is fixed soon. It's a show-stopper for me on an important project.

Once again, the Feedback number is FB18587743.

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Answer 6

simon_ OP

5d

I am seeing the same issue in Beta 3

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Answer 7

Janne OP

4d

Me too, on 2 apps in our portfolio... Showstopper. Posted a feedback: FB18876143

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