Fix macOS "System UID" CPU Usage

Is a process named syspolicyd or trustd pinning your CPU at 100% on macOS Tahoe?

Recommended Troubleshooting Tool

Before proceeding with manual fixes, we recommend using CleanMyMac X. Quickly identify high CPU apps and optimize system memory with one click.

- [Download CleanMyMac X Free Here](#)

- [Browse 240+ Premium Mac Utilities on Setapp](#)

The Symptom

The Mac becomes hot and sluggish. Activity Monitor shows high CPU usage for system security daemons after installing a new app.

The Fix

1. Clear the Security Policy Database

The syspolicyd daemon can get stuck checking app signatures. Run:

sudo spctl --master-disable
sudo spctl --master-enable

*(This toggles the Gatekeeper engine off and back on to reset its state.)*

1. Purge the Trust Cache

Clear the certificate trust store:

sudo killall -9 trustd
sudo rm -rf /Library/Keychains/crls/*

1. Check for "Translocation" Issues

If you run apps directly from the "Downloads" folder, macOS uses extra CPU to run them in a virtual sandbox. Move the app to /Applications to stop this behavior.

Pro Tip

If the CPU usage stays high, look for a "Legacy System Extension" in System Settings > General > Extensions. Old kernel extensions are the #1 cause of syspolicyd hangs.