Fix Sensor port conflicts
Updated
For developers running local services on the same device as Cortex.
Cortex's local ports
Cortex uses these local ports:
| Port | Cortex use |
|---|---|
9000 | Local relay and Sensor status |
9001 | Browser proxy |
19090 | Browser routing configuration file |
A development server or another Cortex process on one of these ports can prevent Cortex from starting.
Fix a port conflict
If Cortex could not start and Port owners appears:
- Open Sensor. Under the startup error, expand Port owners and note the port and process.
- If the process is a development service you own, stop it or configure it to use another port.
- If the process is another Cortex instance, quit that instance from the Cortex menu. On macOS, you can also stop the known Cortex process in Activity Monitor.
- Select Start Cortex, then Run checks.

The conflict is fixed when the status at the top of Sensor shows Running and the startup error no longer appears.
If you do not recognize the process, include the port-owner details when you contact the Chaos Labs team.
After Cortex starts, use Verify Sensor setup to confirm that a new prompt is captured and synced.
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