- Syslogd high CPU – quick profile
- What syslogd does on a Mac
- Why syslogd can hog CPU on Mac
- Symptoms of syslogd CPU overuse
- How to fix syslogd high CPU usage on Mac
- Reboot and check Activity Monitor again
- Use Console to find the noisy process
- Tame or update the offending app or service
- Audit Login Items and background services
- Check disk space and run First Aid
- Boot into Safe Mode (to rule out third-party add-ons)
- Install macOS and app updates
- Scan for adware and PUAs, just in case
- How to keep syslogd from acting up again
- FAQ
Every so often, a legitimate background service on a Mac decides to throw its weight around. Fans ramp up, apps drag behind your clicks, and Activity Monitor points to a process you’ve probably never looked at before: syslogd.
So what job does syslogd actually handle, why can it suddenly chew through CPU as if there’s no tomorrow, and most importantly, how do you fix it without damaging logging or diagnostics you might rely on later? Let’s walk through it in a structured way, and then get practical.
Syslogd high CPU – quick profile
| Property | Details |
|---|---|
| Name | syslogd high CPU / resource overuse |
| Process | syslogd (system logging daemon) |
| Category | System process, potential resource hog |
| Legitimate? | Yes, it’s part of macOS logging infrastructure, not malware |
| Typical trigger | Another app or daemon flooding the log with errors, misconfigured services, leftover LaunchDaemons, debug logging left on, or rare macOS bugs |
| Main symptoms | Mac slows to a crawl, fans run constantly, battery drain, frequent beachballs, syslogd near the top of Activity Monitor’s CPU tab |
| Severity | Low to medium (annoying performance hit, but rarely data loss) |
| Recommended action | Identify the chatty process behind syslogd, fix or remove the culprit, tidy login items and LaunchAgents, install macOS updates, and scan for adware / PUAs if behavior looks suspicious |
What syslogd does on a Mac
Syslogd works as a logging workhorse for macOS. It runs as a daemon, collects log messages from the kernel, system frameworks, daemons, and user applications, then routes those messages to the right logging back end.
Current macOS versions pair syslogd with Apple’s Unified Logging system, which stores structured log data in a central, high-performance store rather than simple flat text files under /var/log. You reach that data mainly through Console.app or the log command-line tool located at /usr/bin/log.
In day-to-day terms, syslogd plays dispatcher for events:
- Apps, daemons, and the operating system shout “this just happened.”
- Syslogd catches each message, attaches metadata like timestamp, process ID, and severity, then hands it off to be stored or shown.
- Admins, support teams, and power users later inspect those logs to troubleshoot or investigate incidents.
Under normal conditions, syslogd barely shows up. It takes tiny CPU slices and stays out of the way. Once some component starts dumping messages into the log stream nonstop, the dispatcher has to keep up, and CPU usage spikes. That’s when you notice it.
Why syslogd can hog CPU on Mac
When syslogd climbs to the top of the CPU chart, it usually isn’t the real culprit. Think of it as the messenger stuck in a flood of messages. Something else screams into the log system; syslogd just processes the noise.
According to our analysts, most cases fall into a handful of patterns.
1. Another process spams the log
The classic scenario: a process hits an error loop and logs the same message several times per second. Syslogd processes every single entry and burns CPU as a result.
Many users report trustd, nsurlsessiond, or related network and security services throwing repeated failures, while syslogd’s CPU share climbs as collateral damage.
Other frequent offenders:
- Broken VPN or proxy tools that constantly retry failed connections.
- Third-party security products that log every event at debug level.
- Cloud sync clients stuck on the same file or folder, sending the same error over and over.
If Console shows one line repeating almost continuously, you probably just found the real trigger.
2. Leftover or broken LaunchDaemons / LaunchAgents
Syslogd also tends to work harder when a LaunchDaemon or LaunchAgent keeps failing to start and logs an error every time. Users who migrated systems, performed archive-style upgrades, or removed apps by dragging them to the Trash hit this more often.
A leftover service that points to an app or binary that no longer exists will:
- Try to start.
- Fail at once.
- Log the failure.
- Try again soon after.
From syslogd’s point of view, that loop never ends.
3. Verbose or debug logging left enabled
Developers, support teams, and power users sometimes turn on debug or verbose logging. That switch works fine for short diagnostics, but if a component stays in that mode for days or weeks, it can flood the logging system.
Examples:
- Command-line flags that enable verbose logging for daemons.
- Hidden preferences that crank up logging for networking, Bluetooth, or filesystem modules.
- Third-party apps with a “detailed logging” or “debug logging” box left checked.
Syslogd again sits in the middle, forced to process every extra line.
4. Disk or logging issues
Once log files grow huge or your Mac runs low on disk space, logging becomes less efficient and a lot more repetitive. Syslogd then wastes time on things like:
- Repeated attempts to rotate logs.
- Errors about failed writes.
- Retries as storage gets close to full.
Heavily used systems, or Macs that stay up for very long stretches without a reboot, show this pattern more often. You see syslogd chewing CPU while the rest of the system feels sticky and slow.
5. Rarely, malware or very noisy adware
Syslogd itself doesn’t act as malware. But junkware and adware that crash, misbehave, or tinker with network and browser settings can flood the logs indirectly. Browser hijackers, scareware, and sketchy add-ons that hook into low-level components and then fail loudly when something changes create a constant stream of warnings and errors.
We think this scenario still appears less often than a plain misconfigured app, yet you shouldn’t ignore it if you also notice other signs of compromise.
Symptoms of syslogd CPU overuse
Most users feel the impact before they even know syslogd exists:
- Fans spin up fast and stay loud.
- Apps stutter, trigger beachballs, or take ages to open.
- MacBook batteries lose charge much faster than normal.
- The machine runs hot even with no demanding workload.
Open Activity Monitor (Applications > Utilities) and sort the CPU tab by % CPU. When syslogd sits near the top for long periods, especially in the 50–100% range or above, you have a strong lead. On multi-core CPUs, total usage can show values above 100%, since each core counts as 100%.
Another clear sign: in Console.app, the main log view scrolls almost nonstop, with the same message or small group of messages repeating every fraction of a second.
How to fix syslogd high CPU usage on Mac
Start with simple moves, then add more detailed checks if the problem persists.
1. Reboot and check Activity Monitor again
A restart clears temporary glitches, incomplete log sessions, and stuck services.
After the reboot:
- Launch Activity Monitor.
- Sort processes by % CPU.
- Watch syslogd for a few minutes.
If the spike doesn’t return, you probably hit a one-off issue and don’t need to go further right now.
2. Use Console to find the noisy process
If syslogd still misbehaves, you need to see who’s flooding the log.
- Open Console (Applications > Utilities > Console).
- In the sidebar, pick All Messages or your Mac under “Devices” on older systems.
- Let the log run while syslogd sits high in Activity Monitor.
- Watch for lines that repeat rapidly, often several times per second.
- Check the Process column for those lines; that name likely points to the offender.
Threads on Apple Support Communities often show syslogd high CPU alongside constant messages from services like trustd or nsurlsessiond. That pattern confirms that syslogd just reacts to somebody else’s noise.
Once you know the process name, you can apply targeted fixes.
3. Tame or update the offending app or service
What you do next depends on which component floods the log.
Third-party app
- Quit the app and see whether syslogd calms down.
- Update the app to the latest release.
- If the software looks old or abandoned, consider removing it cleanly using the vendor’s uninstaller or documented steps.
Cloud / sync software (Dropbox, older Google Drive, etc.)
- Pause syncing or quit the client for a while.
- Sign out and sign back in if logs mention authentication errors or specific folders.
Network / VPN / proxy tools
- Disable the VPN profile or proxy from within the app or from System Settings.
- Remove obsolete VPN or proxy configurations in System Settings > Network > VPN or under Filters / Proxies, depending on your version and tools.
Apple daemons such as trustd / nsurlsessiond
- Check your network connection and any active content filters.
- If you recently changed certificates, VPNs, or proxy settings, revert those changes and restart the Mac.
Once you stop or update the noisy component and the repeating log entries disappear, syslogd should fall back to its usual minimal CPU use.
4. Audit Login Items and background services
If the Mac only misbehaves around login or after it runs for a while, a background helper might drive the log storm.
On macOS Ventura and newer:
- Open System Settings > General > Login Items.
- Under Open at Login, disable items you don’t actually need.
- Under Allow in Background, turn off suspicious or unused entries.
On older macOS versions:
- Open System Preferences > Users & Groups.
- Select your user and open the Login Items tab.
- Remove unnecessary entries with the “–” button.
If syslogd quiets down after this cleanup, you probably hit a noisy helper or supporting tool.
Optional: look for leftover LaunchAgents / LaunchDaemons
For persistent problems after app removal, check for orphaned services.
In Finder, choose Go > Go to Folder… and review these paths one by one:
~/Library/LaunchAgents/Library/LaunchAgents/Library/LaunchDaemons
Look for items that clearly belong to software you removed long ago.
If you feel confident that a .plist relates to something you no longer use, move it to a backup folder, maybe on your Desktop, and reboot.
The idea is simple: stop broken services from constantly failing and logging errors, without randomly deleting system files. When you feel unsure, leave the file in place.
5. Check disk space and run First Aid
Logging and low disk space rarely mix well.
- In Finder, select your startup disk and press Command + I to see free space. Keeping at least 10–15% free usually works as a safe buffer.
- Open Disk Utility (Applications > Utilities).
- Select your startup volume and run First Aid to scan and repair filesystem issues.
If the disk ran near full or carried minor corruption, this step alone can reduce the pressure on syslogd and related services.
6. Boot into Safe Mode (to rule out third-party add-ons)
Safe Mode loads only core macOS components and disables most third-party extensions and login items. It acts as a quick filter.
On Apple silicon Macs:
- Shut down the Mac.
- Press and hold the power button until you see “Loading startup options.”
- Choose your startup disk, hold Shift, and click Continue in Safe Mode.
On Intel Macs:
- Restart and hold Shift immediately.
- Release it when the login window appears.
Use the Mac in Safe Mode for a while and keep an eye on Activity Monitor:
- If syslogd stays calm, a third-party extension or login item almost certainly drives the spike.
- If syslogd still spins, you probably face a system-level bug or a noisy Apple component.
Afterward, you can narrow things down by re-enabling login items and background apps gradually in normal mode. A bit of trial and error, yes, but it works.
7. Install macOS and app updates
Apple delivers fixes for logging, network, and security components through regular updates. Keeping macOS current removes a lot of known glitches that produce excessive log chatter.
- Go to System Settings > General > Software Update (or System Preferences > Software Update on older systems).
- Install any pending macOS updates.
- Update key third-party apps via the App Store or their built-in update tools.
If syslogd problems started right after a major OS upgrade, a later point release often stabilizes the affected services.
8. Scan for adware and PUAs, just in case
If you notice browser redirects, aggressive pop-ups, or strange menu bar tools alongside the syslogd spike, check for adware and potentially unwanted apps. Mac adware often causes side effects: performance issues, strange network activity, and odd process behavior.
Run a full scan with a reputable macOS security tool and keep its definitions current. You’re not “repairing syslogd” directly; you’re removing any rogue software that keeps crashing, misfiring, or hammering the logs behind the scenes.
How to keep syslogd from acting up again
Once you restore normal behavior, a few habits help prevent a repeat:
- Choose startup apps carefully. If something doesn’t need to run nonstop, don’t let it auto-launch.
- Avoid leaving debug logging active. When you enable verbose logging for troubleshooting, turn it off once you finish.
- Keep macOS and your main apps updated. Many strange high-CPU issues quietly disappear after routine updates.
- Maintain breathing room on your disk and reboot from time to time to clear accumulated clutter.
- Stick with reputable software sources. This approach lowers the chance of installing noisy, poorly written, or outright malicious tools that abuse system services.
Do that, and syslogd goes back to its usual job: writing logs quietly in the background, with no drama.
FAQ
1. Is syslogd a virus or malware??
No. Syslogd runs as a legitimate system daemon that handles logging on macOS. Unix-like systems have relied on this kind of service for decades. It plays a key role in diagnostics and auditing. High CPU usage from syslogd usually signals trouble elsewhere, typically a chatty or misconfigured process, not an infection on its own.
2. Can I just force-quit syslogd in Activity Monitor?
You can force-quit it, but macOS almost always restarts it immediately because the system needs logging. Killing syslogd might give a short break from high CPU, yet if you ignore the process that spams logs, the spike returns. Fixing the root cause works far better and stays safer.
3. Is it safe to disable syslogd or system logging entirely??
Turning off syslogd or hacking around logging creates more risk than benefit. You lose critical diagnostics, weaken security visibility, and might trigger odd behavior in other macOS components. The right move is to silence the component that floods logs, not to shut down the messenger for good.
4. What if I can’t figure out which process causes the log spam??
If Console doesn’t highlight a single clear offender, follow the layered path: Safe Mode, trimming login items, applying macOS updates, and scanning for adware and PUAs. When syslogd behaves in Safe Mode but misbehaves on a normal boot, some third-party element definitely plays a role, even if the exact process stays unclear at first.
In that situation, grab screenshots or log samples and share them with Apple Support or a trusted Mac technician for another opinion. Honestly, a second set of eyes often spots patterns you miss when you’re too close to the problem.