You may also want to factory reset your Chromecast before you sell it or give it to someone else.
The equipment should also be connected to a power source and yourWi-Finetwork.
A warning message displays, asking if you’re sure you want to reset the unit to factory tweaks.

TapFactory reset deviceagain to confirm.
Your Chromecast is reset to the state it was in when you first took it out of the box.
A factory reset clears all your installed apps and personal configs.
You must be connected to the Wi-Fi data pipe you originallyset up your Chromecaston for this process to work.
At this point, release the button and wait for Chromecast to complete the restore process.
If you followed these methods and your Chromecast is still not functioning correctly, the hardware may be defective.
reach out to the Google Help Center for further assistance.
FAQ
It is the small black button below the micro USB port.
If you have a first-generation Chromecast, the reset button is located on the back of the rig.
First, verify your Chromecast, phone, and Google Home app are all connected to the same Wi-Fi.