How do I fix Safari Service Worker High CPU in macOS Tahoe 26.2?

Three approaches in order of safety: (1) Clear Safari Service Workers; (2) Reset Safari Networking. Full Terminal commands and System Settings paths are inside each section.

Is this fix confirmed for macOS Tahoe 26.2?

Yes — verified on macOS Tahoe 26.2. Article is updated when Apple ships a point release that changes the symptom or fix.

How to Fix Safari Service Worker High CPU in macOS Tahoe 26.2

Symptom: Safari on macOS Tahoe causes high CPU usage even when all tabs are closed. Activity Monitor shows com.apple.WebKit.Networking using 100%+ CPU.

TL;DR fix

Start with Fix 1: Clear Safari Service Workers. If the issue persists after that, try Fix 2: Reset Safari Networking. Full Terminal commands and step-by-step instructions are in each section below.

Why this happens

Legacy service workers from sites like YouTube or Slack can get stuck in an infinite update loop within Tahoe's new Safari sandbox.

Recommended Troubleshooting Tool

Before proceeding with manual fixes, we recommend using CleanMyMac X. Excellent for clearing Safari caches, bloated databases, and stuck background processes.

Fix 1: Clear Safari Service Workers

Open Terminal.
Run the following command to purge the worker cache:

rm -rf ~/Library/Containers/com.apple.Safari/Data/Library/Caches/com.apple.WebKit.Networking/ServiceWorkerCache

Force-quit Safari and relaunch.

Fix 2: Reset Safari Networking

In Terminal:

killall com.apple.WebKit.Networking

Recommended Tool: 1Password

To reduce the number of active background extensions and workers:

- Get 1Password for a highly optimized extension that doesn't trigger the WebKit networking loops common with legacy password managers.

Tested and documented by the MacDebug team — about MacDebug. See also Safari Freezing or Crashing on macOS Tahoe 26.2, VoiceOver Not Working Properly in Safari on Sequoia, or browse all guides on macdebug.