macOS processes › Core system
What is syslogd on Mac?
syslogd is the traditional Unix system log daemon. On current macOS it handles older-style log messages and a few text log files, while most logging goes through logd.
What it does
Apps and command-line tools that use the classic syslog interface send their messages to syslogd, which can write them to text files in /var/log, such as system.log. Its job is much smaller than it was before Apple introduced unified logging, but it still runs on every Mac.
Why it gets busy
- An older app or command-line tool sending a flood of syslog messages.
- A process stuck in an error loop that reports every failure.
Why is syslogd using so much CPU?
syslogd is busy when something keeps sending it messages, usually an older app or tool stuck in an error loop. The newest lines of system.log in Console name the sender.
Is it safe to quit?
Quitting it loses log messages and doesn't stop whatever is sending them.
How to calm it down
- Open Console, choose system.log under Log Reports, and look at the newest lines to see who's writing.
- Update or remove the app or tool that's logging nonstop.
- If the sender is part of macOS, restart and install any pending macOS update.
In SystemWatch
SystemWatch explains syslogd next to logd so you know which one is actually busy, and History shows when the logging burst started.
