Hi, I’m implementing a macOS DNS Proxy as a system extension and running into a persistent activation error: OSSystemExtensionErrorDomain error 9 (validationFailed) with the message: extension category returned error This happens both on an MDM‑managed Mac and on a completely clean Mac (no MDM, fresh install). Setup macOS: 15.x (clean machine, no MDM) Xcode: 16.x Team ID: AAAAAAA111 (test) Host app bundle ID: com.example.agent.NetShieldProxy DNS Proxy system extension bundle ID: com.example.agent.NetShieldProxy.dnsProxy The DNS Proxy is implemented as a NetworkExtension system extension, not an app extension. Host app entitlements From codesign -d --entitlements :- /Applications/NetShieldProxy.app: xml com.apple.application-identifier AAAAAAA111.com.example.agent.NetShieldProxy <key>com.apple.developer.system-extension.install</key> <true/> <key>com.apple.developer.team-identifier</key> <string>AAAAAAA111</string> <key>com.apple.security.app-sandbox</key> <true/> <key>com.apple.security.application-groups</key> <array> <string>group.com.example.NetShieldmac</string> </array> <key>com.apple.security.files.user-selected.read-only</key> <true/> xml com.apple.application-identifier AAAAAAA111.com.example.agent.NetShieldProxy.dnsProxy <key>com.apple.developer.networking.networkextension</key> <array> <string>dns-proxy-systemextension</string> </array> <key>com.apple.developer.team-identifier</key> <string>AAAAAAA111</string> <key>com.apple.security.application-groups</key> <array> <string>group.com.example.NetShieldmac</string> <string>group.example.NetShieldmac</string> <string>group.example.agent.enterprise.macos</string> <string>group.example.com.NetShieldmac</string> </array> DNS Proxy system extension Info.plist On the clean Mac, from: bash plutil -p "/Applications/NetShieldProxy.app/Contents/Library/SystemExtensions/com.example.agent.NetShieldProxy.dnsProxy.systemextension/Contents/Info.plist" I get: json { "CFBundleExecutable" => "com.example.agent.NetShieldProxy.dnsProxy", "CFBundleIdentifier" => "com.example.agent.NetShieldProxy.dnsProxy", "CFBundleName" => "com.example.agent.NetShieldProxy.dnsProxy", "CFBundlePackageType" => "SYSX", "CFBundleShortVersionString" => "1.0.1.8", "CFBundleSupportedPlatforms" => [ "MacOSX" ], "CFBundleVersion" => "0.1.1", "LSMinimumSystemVersion" => "13.5", "NSExtension" => { "NSExtensionPointIdentifier" => "com.apple.dns-proxy", "NSExtensionPrincipalClass" => "com_example_agent_NetShieldProxy_dnsProxy.DNSProxyProvider" }, "NSSystemExtensionUsageDescription" => "SYSTEM_EXTENSION_USAGE_DESCRIPTION" } The DNSProxyProvider class inherits from NEDNSProxyProvider and is built in the system extension target. Activation code In the host app, I use: swift import SystemExtensions final class SystemExtensionActivator: NSObject, OSSystemExtensionRequestDelegate { private let extensionIdentifier = "com.example.agent.NetShieldProxy.dnsProxy" func activate(completion: @escaping (Bool) -> Void) { let request = OSSystemExtensionRequest.activationRequest( forExtensionWithIdentifier: extensionIdentifier, queue: .main ) request.delegate = self OSSystemExtensionManager.shared.submitRequest(request) } func request(_ request: OSSystemExtensionRequest, didFailWithError error: Error) { let nsError = error as NSError print("Activation failed:", nsError) } func request(_ request: OSSystemExtensionRequest, didFinishWithResult result: OSSystemExtensionRequest.Result) { print("Result:", result.rawValue) } } Runtime behavior on a clean Mac (no MDM) config.plist is created under /Library/Application Support/NetShield (via a root shell script). A daemon runs, contacts our backend, and writes /Library/Application Support/NetShield/state.plist with a valid dnsToken and other fields. The app NetShieldProxy.app is installed via a notarized, stapled Developer ID .pkg. The extension bundle is present at: /Applications/NetShieldProxy.app/Contents/Library/SystemExtensions/com.example.agent.NetShieldProxy.dnsProxy.systemextension. When I press Activate DNS Proxy in the UI, I see in the unified log: text NetShieldProxy: [com.example.agent:SystemExtensionActivator] Requesting activation for system extension: com.example.agent.NetShieldProxy.dnsProxy NetShieldProxy: [com.example.agent:SystemExtensionActivator] SystemExtensionActivator - activation failed: extension category returned error (domain=OSSystemExtensionErrorDomain code=9) NetShieldProxy: [com.example.agent:SystemExtensionActivator] SystemExtensionActivator - OSSystemExtensionError code enum: 9 NetShieldProxy: [com.example.agent:SystemExtensionActivator] SystemExtensionActivator - validationFailed And: bash systemextensionsctl list -> 0 extension(s) There is no prompt in Privacy & Security on this clean Mac. Question Given: The extension is packaged as a system extension (CFBundlePackageType = SYSX) with NSExtensionPointIdentifier = "com.apple.dns-proxy". Host and extension share the same Team ID and Developer ID Application cert. Entitlements on the target machine match the provisioning profile and Apple’s docs for DNS Proxy system extensions (dns-proxy-systemextension). This is happening on a clean Mac with no MDM profiles at all. What are the likely reasons for OSSystemExtensionErrorDomain error 9 (validationFailed) with "extension category returned error" in this DNS Proxy system extension scenario? Is there any additional configuration required for DNS Proxy system extensions (beyond entitlements and Info.plist) that could trigger this category-level validation failure? Any guidance or examples of a working DNS Proxy system extension configuration (host entitlements + extension Info.plist + entitlements) would be greatly appreciated. Thanks!

I’m building a macOS app with a DNS Proxy system extension for Developer ID + notarization, deployed via MDM, and Xcode fails the Developer ID Release build with a provisioning profile mismatch for com.apple.developer.networking.networkextension. Environment macOS: Sequoia (15.7.2) Xcode: 26.2 Distribution: Developer ID + notarization, deployed via MDM Host bundle ID: com.mydns.agent.MyDNSMacProxy DNS Proxy system extension bundle ID: com.mydns.agent.MyDNSMacProxy.dnsProxy Host entitlements (Release): File: MyDNSMacProxy/MyDNSMacProxyRelease.entitlements: "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>com.apple.application-identifier</key> <string>B234657989.com.mydns.agent.MyDNSMacProxy</string> <key>com.apple.developer.networking.networkextension</key> <array> <string>dns-proxy</string> </array> <key>com.apple.developer.system-extension.install</key> <true/> <key>com.apple.developer.team-identifier</key> <string>B234657989</string> <key>com.apple.security.app-sandbox</key> <true/> <key>com.apple.security.application-groups</key> <array> <string>group.com.mydns.MyDNSmac</string> </array> <key>keychain-access-groups</key> <array> <string>B234657989.*</string> </array> </dict> </plist> xcodebuild -showBuildSettings -scheme MyDNSMacProxy -configuration Release : PROVISIONING_PROFILE_SPECIFIER = main MyDNSMacProxy5 CODE_SIGN_IDENTITY = Developer ID Application Host Developer ID profile main_MyDNSMacProxy5.provisionprofile (via security cms -D): "Entitlements" => { "com.apple.application-identifier" => "B234657989.com.mydns.agent.MyDNSMacProxy" "com.apple.developer.team-identifier" => "B234657989" "com.apple.security.application-groups" => [ "group.com.mydns.MyDNSmac", ..., "B234657989.*" ] "keychain-access-groups" => [ "B234657989.*" ] "com.apple.developer.system-extension.install" => 1 "com.apple.developer.networking.networkextension" => [ "packet-tunnel-provider-systemextension", "app-proxy-provider-systemextension", "content-filter-provider-systemextension", "dns-proxy-systemextension", "dns-settings", "relay", "url-filter-provider", "hotspot-provider" ] } So: App ID, team ID, keychain and system‑extension.install match. The profile’s com.apple.developer.networking.networkextension is a superset of what I request in the host entitlements (dns-proxy only). System extension (for context) DNS Proxy system extension target: NSExtensionPointIdentifier = com.apple.dns-proxy NetworkExtension → NEProviderClasses → com.apple.networkextension.dns-proxy → my provider class Entitlements: com.apple.developer.networking.networkextension = ["dns-proxy-systemextension"] This target uses a separate Developer ID profile and builds successfully. Xcode error Release build of the host fails with: …MyDNSMacProxy.xcodeproj: error: Provisioning profile "main MyDNSMacProxy5" doesn't match the entitlements file's value for the com.apple.developer.networking.networkextension entitlement. (in target 'MyDNSMacProxy' from project 'MyDNSMacProxy') Xcode UI also says: Entitlements: 6 Included, 1 Missing Includes com.apple.developer.team-identifier, com.apple.application-identifier, keychain-access-groups, com.apple.developer.system-extension.install, and com.apple.security.application-groups. Doesn’t match entitlements file value for com.apple.developer.networking.networkextension. Because of this, the app bundle isn’t produced and I can’t inspect the final signed entitlements. Questions: For com.apple.developer.networking.networkextension, should Xcode accept a subset of values in the entitlements (here just dns-proxy) as long as that value is allowed by the Developer ID profile, or does it currently require a stricter match? Is the following configuration valid for Developer ID + MDM with a DNS Proxy system extension: Host entitlements: ["dns-proxy"] System extension entitlements: ["dns-proxy-systemextension"] Host profile’s NE array includes the DNS Proxy system extension types. If this is a known limitation or bug in how Xcode validates NE entitlements for Developer ID, is there a recommended workaround? Thanks for any guidance.