How to Restart Gertrude’s Mac Filter

The Gertrude macOS app is really two apps in one—the main user-facing app with the menu bar icon, and the internet filter system extension. The filter runs as a separate process under a separate user so that it can filter network traffic. These two apps have to communicate, and sometimes that communication breaks down. Usually the health-check screen can both diagnose and fix this sort of problem, but sometimes you’ll need to manually remove the filter in order to get things working correctly again.

Manually remove the filter

Open the Apple menu and go to System Settings → Network. Next, click Filters. You should see the Gertrude filter listed under “Filters & Proxies.” Select it and click the minus icon to remove the filter.

Once you’ve removed the filter, you should be able to restart it from the Gertrude app menu bar dropdown, and it’s likely the connection and communication will be reestablished.

Restart the computer

In some rare cases, especially when the app and the filter can’t seem to communicate, and no other steps have fixed it, fully shutting down and restarting the computer often will fix the problem.