macOS processes › Core system
What is logd on Mac?
logd is the macOS unified logging daemon. It collects log messages from apps and system processes and stores them so Console and troubleshooting tools can read them.
What it does
Most of macOS and many apps record what they're doing as log messages. logd gathers them, compresses them, and keeps them in a system log store, removing older entries as limits are reached. When you stream messages in the Console app, logd is the source.
Why it gets busy
- A process writing huge numbers of log messages, usually because something is failing and retrying.
- Console or another tool streaming logs with extra detail turned on.
- Collecting a diagnostic report, which pulls in a lot of logs at once.
- Security or monitoring software with verbose logging turned on.
Why is logd using so much CPU?
logd's CPU reflects how much everything else is logging. When it's high, some process is writing messages nonstop. Console's live stream shows which one, and fixing that process calms logd.
Is it safe to quit?
macOS relaunches it, but messages from that moment are lost, and the process flooding it keeps going.
How to calm it down
- Open Console, click Start streaming, and see which process name fills the list. That's the source.
- Update, reconfigure or remove the noisy app. For security tools, check for a debug or verbose logging option.
- Stop streaming in Console when you're done, since live streaming adds work for logd.
- Restart your Mac if a system process seems stuck in an error loop.
In SystemWatch
SystemWatch's History shows how long logd stayed busy, and comparing it with other processes over the same window points to the one flooding the log.
