And somehow I duplicated my post... lol, good times.

I will file a bug report. Any complex UI that takes more than a few seconds to render the preview will cause this issue in Xcode 16. Below is an example view that takes a while to render in preivew. This allows you to run debug while the preview is still rendering. The result is the app loads twice with two icons in the dock. I'll post a bug number once I submit. import SwiftUI struct ComplexView: View { let itemCount = 10_000 var gradientColors: [Color] = [.blue, .purple, .pink, .red, .orange, .yellow] var body: some View { ScrollView { VStack { Text("Rendering Complex View") .font(.largeTitle) .padding() // Heavy Custom Graphics and Layered Canvas Drawing Canvas { context, size in let gradient = Gradient(colors: gradientColors) // Correcting the gradient fill context.fill(Path(ellipseIn: CGRect(x: 0, y: 0, width: size.width, height: size.height)), with: .linearGradient(gradient, startPoint: .zero, endPoint: CGPoint(x: size.width, y: size.height))) // Stroked ellipses to add complexity for i in 1..<50 { let rect = CGRect(x: CGFloat(i) * 10, y: CGFloat(i) * 10, width: size.width / 2, height: size.height / 2) context.stroke(Path(ellipseIn: rect), with: .color(.black), lineWidth: 1) } } .frame(height: 500) .padding() // Expensive ForEach with Thousands of Views ForEach(0..<itemCount, id: \.self) { index in HStack { Circle() .fill(gradientColors[index % gradientColors.count]) .frame(width: 30, height: 30) .shadow(radius: 10) Text("Item \(index)") .font(.headline) .foregroundColor(.primary) } .padding(.vertical, 2) } } } } } struct ComplexView_Previews: PreviewProvider { static var previews: some View { ComplexView() } }

@DTS Engineer Feedback Assistant filed FB15436443 And yes, this really matters. Debugging an app with duplicate runtimes is not expected behavior from an IDE. I noticed it the first time I ran a debug session after upgrading. How this made it past Q/A at Apple is beyond comprehension.

Feedback Assistant report filed FB15540812

After some additional reading, it looks like I need to look at Finder Extensions not Sync extensions. Back to the drawing board!

More research done and it looks like I was on track with FinderSync... however with Sequoia, there is no panel to enable them! Must be done by command line. C'mon Apple. https://developer.apple.com/forums/thread/756711

I'm just learning about FinderSync and decided to start up a test project, ran straight into this issue with Sequoia today. If I file a Feedback Assistant, should I reference https://feedbackassistant.apple.com/feedback/15249290 ? If Apple is going to remove/deprecate, just let us know so we can stop banging our heads against the wall. 😵‍💫

A good read on how these settings have "changed" over the years. https://fileutils.com/blog/sync-my-finder/6

Thank you for the detailed reply @DTS Engineer. Much appreciated!

@ProofOfDragons @Max_Dillinger , if you could both use Feedback Assistant and reference my submission, FB15436443, it may help to gain attention of Apple and get this resolved. Thanks.