To factory reset a Cisco Catalyst 9200 series switch (e.g. when you can no longer log in or have forgotten the password), you can factory reset the switch through physical access and a serial console connection.

First, connect the serial console cable and verify whether you have access to the serial console. Also, verify whether you have physical access to the switch and can unplug the power.

Unplug the power cable to power down the switch. While holding down the button at the left top corner (next to the "S" LED), plug in back in. Keep the button pressed for at least 10 seconds, until the "S" LED is solid green. The console output will also state the boot from "pa  ...