I would add that I think the difference between Logic and hosts that do not experience the issue is opening the AU "out of process" vs "in process" Here is my Feedback Assistant ticket. FB18911349 (UIDocumentBrowserViewController bug in Audiounit while keyboard is connected)

I've created a small demo project using the FilterDemoExample https://github.com/olympianoiseco/AudiounitFileBrowserBug/tree/main

@eskimo Is it possible to download the older/fixed version of instruments somewhere? And would it work with newer versions of Xcode?

Thanks. The relevant piece that I was missing is that it's not just the literal topLevelClasses that need to be registered with the NSSecureUnarchiveFromDataTransformer, but also any classes contained in the transformable if it's a collection. Therefore, if my NSDictionary has a custom class inside it, I need to register a subclass of NSSecureUnarchiveFromDataTransformer to allow that class. @objc class DataTransformer: NSSecureUnarchiveFromDataTransformer { static let name = NSValueTransformerName(rawValue: String(describing: DataTransformer.self)) @objc(registerValueTransformer) public static func register() { let transformer = DataTransformer() print(DataTransformer.allowedTopLevelClasses) ValueTransformer.setValueTransformer(transformer, forName: name) } override class var allowedTopLevelClasses: [AnyClass] { var topLevelClasses = super.allowedTopLevelClasses let myClasses = [MyClass.self, MyOtherClass.self] topLevelClasses.append(contentsOf: myClasses) return topLevelClasses } }

FIXED * Though I had setup up the correct profile for the "Release" build, the "Debug" build needed it's own profile, which I had neglected to generate.