notifyd is the server behind notify(3), the lightweight way macOS processes signal simple state changes to each other; it's part of macOS and has nothing to do with Notification Center banners. If it uses a lot of CPU, an app is posting or polling these notifications in a loop, and quitting apps one at a time finds it.
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One Mac, macOS 26.5 (25F71) on Apple silicon, read with ps and codesign on October 29, 2026
| Path | /usr/sbin/notifyd |
|---|---|
| Runs as | root |
| Signed by | Apple (Software Signing), identifier com.apple.notifyd |
notifyd is the macOS daemon that provides the low-level notify(3) notification mechanism used for lightweight inter-process communication. Unlike distnoted (which handles higher-level NSDistributedNotifications), notifyd manages simple state-change tokens that processes use to signal events efficiently — such as timezone changes, network state changes, and DNS configuration updates.
High CPU from a process rapidly checking or posting notifications
Notification token leaks causing memory growth over long uptimes
Delayed system state propagation when notifyd is overloaded
Console messages about notification registration failures
notifyd doesn't report which app is posting. Watch Activity Monitor's CPU view for an app whose CPU rises and falls with notifyd's, then quit that app to test. notifyutil can watch a single notification key ('notifyutil -w <key>'), which helps only once you know the key.
Once you identify the app posting excessive notifications, quit and restart it. Many notification-related issues are caused by a process stuck in a notification loop that resolves when the process is restarted.
Run 'sudo killall notifyd' in Terminal. launchd will restart it immediately. This clears all registered notification tokens and forces all processes to re-register, which resolves token leak and stale registration issues.
notifyd handles notifications for system state changes (timezone, DNS, network). If these seem stuck, restarting notifyd or rebooting resolves the issue. A reboot is the most thorough fix for persistent notification propagation problems.
notifyd using minimal resources in the background is normal — it's a lightweight message broker. Be concerned if it shows high CPU, which indicates a process is either posting or polling notifications at an extremely high rate. This is usually a bug in a specific application rather than a notifyd issue.
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notifyd is the low-level notification daemon on macOS that provides the notify(3) inter-process communication mechanism. Processes register interest in named notification tokens, and when another process posts to that token, all registered listeners are notified. It's used for lightweight system events like timezone changes, DNS updates, and network state changes.
Not directly. notifyd handles low-level system notifications between processes (invisible to users), while Notification Center (managed by usernoted) handles the user-visible notification banners and alerts. They are separate systems that serve different purposes, though some user-facing notifications may be triggered by notifyd events.
Yes. notifyd is a core Apple system daemon that has been part of macOS since the Darwin foundation. It provides essential inter-process communication infrastructure. It is code-signed by Apple, runs as a system service, and is protected by System Integrity Protection.
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