Make sure the Chromecast is plugged in and powered on
Open the Google Home app on your phone or tablet
Select your Chromecast device
Tap Settings
Tap More
Tap Factory reset
Confirm the reset
Or reset it manually on the device
Keep the Chromecast plugged in
Press and hold the reset button on the Chromecast
Hold it until the LED light changes or starts blinking
Release the button when the reset begins
Wait for the Chromecast to restart and reset completely