NSCocoaErrorDomain Error Code 4

What Kevin said plus… It’s reasonable to use different approaches for different subsystems in your app. For example: If you’re fetching an audio file to play immediately, a standard session is probably best. Critically, it results in the least latency, which is important because you’re actively playing that audio. And while this requires your app to not suspend, that’s OK because you’re playing audio. If you’re downloading a large file that the user isn’t actively playing, a background session makes sense. If you’re scanning for updates, you could use a background processing task. This typically runs overnight, which is fine because the user isn’t expecting the results immediately. Unless they bring your app to the foreground and tap the refresh button, in which case you might run the same code immediately. And you can then use a continued processing task to complete the refresh. But that’s just one way to slice this. You have lots of options and it’s kinda up to you to decide which one makes sense b

Hey Quinn, thanks for all the material. I realize that I have a basic issue in my code. data is not loaded. In the previous version, archiver had a connection to data let archiver = NSKeyedArchiver(forWritingWith: data) That's no more the case, so data is empty, hence the problems. let data = NSMutableData() let archiver = NSKeyedArchiver(requiringSecureCoding: true) archiver.encode(myObject, forKey: theKey) archiver.encode(myObject2, forKey: theKey2) archiver.finishEncoding() do { try data.write(to: an uRL, options: []) // data is empty of course ! } catch { } So should I replace: archiver.encode(myObject, forKey: theKey) archiver.encode(myObject2, forKey: theKey2) archiver.finishEncoding() do { try data.write(to: anURL, options: []) // So object and object2 are on file with let data = try! NSKeyedArchiver.archivedData(withRootObject: myObject, requiringSecureCoding: true) let data2 = try! NSKeyedArchiver.archivedData(withRootObject: myObject2, requiringSecureCoding: true) archiver.finishEncoding()

Thanks for the clarification about Developer ID vs Apple Development and for the links. Previously I started with Developer ID and the dns-proxy-systemextension entitlement, but per your advice I’ve now switched both the host app and the DNS Proxy system extension to Apple Development signing and the legacy dns-proxy value. Current Apple Development setup macOS: 15.7.3 (24G419) Xcode: 26.2 (17C52) Host: com.example.agent.MyMacProxy DNS Proxy system extension: com.example.agent.MyMacProxy.dnsProxy System extension entitlement: xml com.apple.developer.networking.networkextension dns-proxy System extension Info.plist (built .systemextension inside the host app): xml NSExtension NSExtensionPointIdentifier com.apple.system_extension.network_extension NSExtensionPrincipalClass MyMacProxy.DNSProxyProvider There is no NetworkExtension key in this plist (confirmed with plutil -p on the built .systemextension in both DerivedData and /Applications). The system extension is embedded at: MyMacProxy.app/Contents/Library/Sy

OK. I don’t think you can optimise beyond that. Rather, I think you should use that as a baseline for performance work as you evolve your program. Speaking of that, An Apple Library Primer has links to various WWDC talks where the linker team discusses various topics. Most notably, the 2022 talk discusses launch times. It’s well worth a watch. Finally, just for context, the libSystem initialiser does a bunch of really critical stuff. For example, it has the code that sets up the App Sandbox, if the executable enables it. If you want to see this initialiser in action, open your true clone project, set a symbolic breakpoint on libSystem_initializer, and run it from Xcode. When you stop at the breakpoint, Xcode will show a page of disassembled code, but that’s not too hard to understand. And most of the symbols are present, so you can look up the source code in Darwin. IMPORTANT The Darwin open source isn’t guaranteed to match the source used to build the OS, but it’s usually close eno

Hey Claude31, it’s nice for me to be helping you for a change (-: It’s hard to tell exactly what’s going wrong here without know more about the objects in play. However, in general, when you decode something from a secure keyed archive, you have to tell the system what type you’re expecting. That’s the key factor is what makes it secure. Over the years I’ve helped a bunch of folks with problems like this. All of these threads have code snippets from me that you should find useful: Question about including all project classes in ofClasses parameter when using NSKeyedUnarchiver.unarchivedObject(ofClasses:from:) Fragment large size data sent and received using NSKeyedArchiver.archivedData in GameCenter Unarchiving an object with custom classes XPC, Swift, ObjC, and arrays NSKeyedUnarchiver decodeObjectOfClasses failed NSKeyedUnarchiver decodeObjectOfClasses failed 'unarchiveTopLevelObjectWithData' was deprecated Use unarchivedObject(ofClass:from:) instead NSkeyedArchiver fails when trying to archive sub