I'm distributing a macOS .pkg installer signed with Developer ID Installer and notarized via notarytool. On macOS 26.3 (Tahoe, Build 25D125), the package is rejected by Gatekeeper when downloaded from the internet. What works: pkgutil --check-signature → signed, Developer ID Installer, full chain (G2 intermediate + Apple Root CA) xcrun stapler validate → "The validate action worked!" xcrun notarytool info <id> → status: Accepted The .app inside the .pkg passes spctl -a -vvv → "accepted, source=Notarized Developer ID" What fails: spctl -a -vvv --type install mypackage.pkg → rejected, origin=Developer ID Installer Raw assessment: assessment:remote = true, assessment:verdict = false Double-clicking the downloaded .pkg shows only "Move to Trash" / "Done" (no "Open" option) syspolicyd log: meetsDeveloperIDLegacyAllowedPolicy = 0 (expected, since the cert is new), but no "notarized" match is logged Certificate details: Developer ID Installer, issued Feb 28, 2026, valid until 2031 OID 1.2.840.113635.100.6.1.14 (Developer ID Installer) — critical OID 1.2.840.113635.100.6.1.33 — timestamp 20260215000000Z Intermediate: Developer ID Certification Authority G2 (OID 1.2.840.113635.100.6.2.6) security verify-cert → certificate verification successful Build process: productbuild --distribution ... --sign <SHA1> (also tried productsign) Both produce: Warning: unable to build chain to self-signed root xcrun notarytool submit → Accepted xcrun stapler staple → worked Workaround: xattr -d com.apple.quarantine ~/Downloads/mypackage.pkg allows opening the installer. Question: Is spctl --type install assessment expected to work differently on macOS 26 Tahoe? The same signing and notarization workflow produces .app bundles that pass Gatekeeper, but .pkg installers are rejected. Is there a new requirement for .pkg distribution on macOS 26? Environment: macOS 26.3 (25D125), Xcode CLT 26.3