What you will achieve
Stop macOS repeatedly asking for login keychain password after login or wake.
Repeated keychain password dialogs usually mean login password changed but login keychain still expects old password, or an app accesses stale certificate. Fix sync before reset — reset deletes all stored credentials for that keychain.
1) Password mismatch
Login keychain password often still matches old Mac login password after change. Keychain Access → login keychain → Change Password for Keychain — set to current login password.
2) Update keychain after reset
- Open Keychain Access.
- If login keychain locked at startup, click Update Keychain Password when prompted after login.
- Enter old and new login passwords correctly once.
3) Stuck prompts for one app
Delete that app’s entries in keychain (search app name) — re-save password in app. Check for duplicate “Internet password” entries for same URL.
4) iCloud Keychain
Apple ID → iCloud → Passwords & Keychain — toggle off/on re-syncs. Wait five minutes before assuming failure.
5) When endless loop persists
Reset default keychain — see reset keychain guide — last resort; re-enter all passwords.
6) Sleep vs login keychain
Separate setting “Lock keychain when sleeping” in Keychain Access → login → Edit Keychain Settings — if lock delay zero, prompts on every wake are expected. Set lock after 5 minutes idle instead.
7) Safari AutoFill split
Safari passwords in iCloud Keychain vs local login keychain — repeated Safari prompt may be iCloud Keychain awaiting approval on another device. Check iPhone Settings → Passwords.
8) MDM keychain payloads
Corporate identity certs auto-renew — if prompt loops after cert roll, remove expired cert in Keychain Access → My Certificates and re-enrol profile.
Verify
Boot and wake without keychain dialogs; Mail and Wi‑Fi autoconnect; one-time auth only for apps that require it.
Additional troubleshooting notes
If steps above do not resolve the issue on the first attempt, reboot once, confirm System Settings → General → Software Update is current, and retry with a second administrator account to rule out profile or keychain corruption in your daily user. Document exact error text from Console.app with timestamp — vague “it still fails” without logs wastes support time. On Apple Silicon, re-test after full shutdown (not just restart) because firmware and Thunderbolt controllers reset only on cold boot. Intel Macs should repeat test in Safe Mode to bypass third-party login items. Before erase or keychain reset, verify Time Machine or clone backup completed — batch 3 guides assume Monterey/Ventura/Sonoma/Sequoia paths in System Settings; search Spotlight for renamed panes if your macOS version labels differ slightly.