Summary We are activating a Network Extension system extension (filter-data) from a signed and notarized macOS app. Activation consistently fails with:
OSSystemExtensionErrorDomain code=4 Extension not found in App bundle. Unable to find any matched extension with identifier: com.seaskylight.yksmacos.ExamNetFilter.data At the same time, sysextd logs:
no policy, cannot allow apps outside /Applications However, our host app and executable real paths are already under /Applications, and the extension bundle physically exists in the expected app bundle location.
Environment macOS: Darwin 25.4.0 Host app: /Applications/xxx.app Host bundle id: com.seaskylight.yksmacos System extension bundle id: com.seaskylight.yksmacos.ExamNetFilter.data Team ID: BVU65MZFLK Device management: Enrolled via DEP: No MDM enrollment: No Reproduction Steps Install host app to /Applications. Launch host app via Finder or: open -a "/Applications/xxx.app" Trigger OSSystemExtensionRequest activationRequestForExtension for: com.seaskylight.yksmacos.ExamNetFilter.data Observe failure callback (code=4). Collect logs: log show --last 2m --style compact --info --debug --predicate 'process == "sysextd"' systemextensionsctl list (shows 0 extension(s)) Observed Results sysextd client activation request for com.seaskylight.yksmacos.ExamNetFilter.data attempting to realize extension with identifier com.seaskylight.yksmacos.ExamNetFilter.data no policy, cannot allow apps outside /Applications App-side diagnostics (captured at failure) pid=3249 bundlePath=/Applications/xxx.app bundlePathReal=/Applications/xxx.app execPath=/Applications/xxx.app/Contents/MacOS/xxx execPathReal=/Applications/xxx.app/Contents/MacOS/xxx extPath=/Applications/xxx.app/Contents/Library/SystemExtensions/ExamNetFilterData.systemextension extExists=true runningFromHelper=false Error callback NSError{domain=OSSystemExtensionErrorDomain code=4 desc=Extension not found in App bundle...} Additional Validation We reproduced the same failure using a minimal native host app (SysExtProbe) in /Applications that only submits the activation request for the same extension identifier. It also fails with OSSystemExtensionErrorDomain code=4, indicating this is not specific to Electron app logic.
Signing / Packaging Notes Host app and system extension are signed with the same Team ID (BVU65MZFLK). System extension bundle exists under: /Applications/xxx.app/Contents/Library/SystemExtensions/ExamNetFilterData.systemextension Extension Info.plist contains bundle id: com.seaskylight.yksmacos.ExamNetFilter.data Host app includes NSSystemExtensionUsageDescription. Questions for DTS In non-MDM personal-device scenarios, what exact conditions trigger sysextd to emit: no policy, cannot allow apps outside /Applications even when both bundlePath and realpath are in /Applications? Can code=4 (“Extension not found in App bundle”) be returned for policy/state reasons even when extension bundle is present and identifier matches? Are there known sysextd policy/cache states that cause this behavior, and what is the recommended recovery procedure?