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.