On macOS 27.2 beta 1/2 our URL filter never starts: the session loops starting -> stopping. The same build works on macOS 27.0 (26A428). Both our TestFlight and notarized standalone builds fail. Prefilter and PIR registration succeed. The PIR status request then fails: NWPath is satisfied, the connection is configured proxy fail closed, proxy strict fail closed, the proxy fails (event: proxy:children_failed), and the error is NSURLErrorDomain -1009 / POSIX 50 "Network is down" with _NSURLErrorPrivacyProxyFailureKey=true. NEMembershipCheckerErrorDomain Code=3 -> NEAgentURLFilterErrorDomain Code=3; the app sees serverSetupIncomplete. The privacy-proxy allow-list entry is identical on macOS 27.0 and 27.2 beta (com.adguard). Disabling the VPN, rebooting, and recreating the URL filter configuration do not help. Log excerpt: neagent: updatePrefilterWithCompletionHandler - result 1 neagent: <NEPIRChecker> - Register with PIR Server (group <com.adguard.safari.AdGuard> ... PrivacyProxyFailOpen <0> ...) -> completed registration ciphermld: [C3 ...] proxy fail closed, proxy strict fail closed ciphermld: [C3.1.1 ... failed proxy (satisfied (Path is satisfied), interface: en0[802.11], ipv4, dns, uses wifi, flow divert agg: 2, LQM: good)] event: proxy:children_failed ciphermld: queryStatus: NSURLErrorDomain -1009 / POSIX 50 "Network is down", _NSURLErrorPrivacyProxyFailureKey=true, NWPath=satisfied neagent: Failed to startFilter <Error Domain=NEMembershipCheckerErrorDomain Code=3 "(null)"> nesessionmanager: NEURLFilterPlugin(com.adguard.safari.AdGuard[url-filter][inactive]): setStatus:error: - err Error Domain=NEAgentURLFilterErrorDomain Code=3 Filed as FB24933164.

macOS 26.6, 26.7, 27.0 and 27.2 beta 1/2. Reproduced with Apple's SimpleURLFilter sample ("Filtering traffic by URL", WWDC25 session 234), built and run as a macOS app. The sample never sets localizedDescription, so I added one line to ConfigurationModel.save(configuration:) before saveToPreferences(): sharedFilterManager.localizedDescription = "Sentinel Filter Name" The property holds the value in memory: after loadFromPreferences(), the logged LocalizedStringResource still has key: "Sentinel Filter Name". But the effective configuration the system starts the session with has no localizedDescription — the session is named after the app: name = SimpleURLFilter applicationName = SimpleURLFilter application = com.example.apple-samplecode.SimpleURLFilterTC3Q7MAJXF (the rest of the nesessionmanager dump is the urlFilter dictionary, and it has no localizedDescription key). System Settings > Network > Filters shows the filter as URLFilter, not "Sentinel Filter Name". The stored configuration (/Library/Preferences/com.apple.networkextension.plist) has no localizedDescription key either, and injecting one by hand does not survive a nesessionmanager restart. Re-saving, removing and re-creating the configuration, and rebooting the Mac do not change the displayed name. Expected: the docs describe localizedDescription as "A string containing a description of the URL filter", and WWDC25 session 234's code sample ("Configure and manage URL Filter") sets it this way (manager.localizedDescription = "Alice's URL Filter"). For comparison, a NETransparentProxyManager configuration on the same Mac persists localizedDescription as the configuration's Name in the same plist, while the URL filter configuration has no such field. Filed as FB24987420.

I am testing NEURLFilter on macOS using the SimpleURLFilter sample, and I am seeing a failure from neagent while it is saving the local URL prefilter Bloom filter to its mmap file. The relevant log is: neagent +[NEBloomFilter mmapToFile:data:dataLength:numberOfBits:numberOfHashes:murmurSeed:tag:]: NEBloomFilter - failed to open mmap file /private/var/db/urlPrefilter/com.apple.networkextension.url-prefilter-data.temp.com.example.apple-samplecode.SimpleURLFilterTC3Q7MAJXF <errno 13 - Permission denied> neagent <NEAgentURLFilterExtension: 0xc8ce64280>: -[NEAgentURLFilterExtension startURLFilter]_block_invoke - Failed to save first fetch of pre-filter data Environment: macOS: 26.5.1 (25F80) Xcode: 26.5 (17F42) Platform: macOS Signing type: Apple Development (automatically manage signing) What I am doing: Build and run the containing app. Save and enable the NEURLFilterManager configuration. The URL filter provider starts. The provider's prefilter code is reached. neagent logs the mmap failure above while trying to open a temporary file under /private/var/db/urlPrefilter. Expected result: neagent should be able to create or open its system-managed URL prefilter cache / mmap file under /private/var/db/urlPrefilter, and the local Bloom filter should be loaded successfully. Actual result: neagent fails to open the temporary mmap file with errno 13 Permission denied: /private/var/db/urlPrefilter/com.apple.networkextension.url-prefilter-data.temp.<bundle/team-specific suffix> I am not manually creating, modifying, or chmod/chown-ing /private/var/db/urlPrefilter or anything inside it. The directory and its contents are entirely system-managed. The failure appears to happen inside neagent while it is handling the system-managed URL prefilter cache. The failure occurs at the mmapToFile: step while neagent saves the Bloom filter prefilter data. Directory state: drwxr-xr-x 2 root wheel 64 /private/var/db/urlPrefilter Has anyone else encountered this? Any suggestions on what could cause neagent to fail with errno 13 on its own mmap file under /private/var/db/urlPrefilter?