How to factory reset an Android phone safely
Short answer
A factory reset erases everything on the phone and returns it to how it was when new. Back up first, make sure you know the Google account email and password on the phone, then use the reset option in Settings. Only reset if restarting and other fixes haven't worked, or if you're selling or giving the phone away.
A factory reset deletes everything. Photos, messages, apps and settings are all erased. Anything you haven't backed up is lost for good.
Before you start
0 of 5 done. Ticking just helps you keep track; nothing is saved or sent.
Steps
Back up and check it worked
Open Settings > Google > Backup and select Back up now. Then open Google Photos to check your pictures are there.
Write down anything you'll need
Wi-Fi password, app logins and any two-step verification apps. If you use an authenticator app, move it to your new phone or set up backup codes first.
Remove the SIM and memory card
If you're selling or giving the phone away.
Open the reset menu
On many phones it's Settings > System > Reset options > Erase all data (factory reset). On Samsung phones it's Settings > General management > Reset > Factory data reset. If you can't find it, search Settings for "reset".
Confirm the reset
Read the list of what will be erased, then confirm. You may need to enter your PIN or password.
Wait
The phone restarts and can take several minutes. Don't switch it off during the reset.
Set it up again, or hand it over
If you're keeping it, sign in with your Google account and choose to restore your backup.
If this happens, try this
If the phone asks for a Google account you don't recognise
It's still linked to the previous owner. Only they can remove it, so contact the seller.
If you've forgotten your Google password
Reset it at the Google account recovery page before you reset the phone.
If the phone won't start properly after the reset
Charge it, then hold power and volume down to restart it. If it keeps failing, stop and get help.
If you're resetting to fix slowness
Try freeing up storage and removing unused apps first. A reset is the last resort.
Things to be careful about
Never reset a phone you've bought second-hand without the seller signing it out of their Google account first.
Don't interrupt a reset by holding the power button.
Recovery-mode resets using button combinations are for when Settings won't open. They can also trigger Factory Reset Protection, so make sure you know the Google login first.
Still stuck?
If you're not sure whether a reset is the right fix, or something goes wrong partway through, the team at SmarterBox Limited, which runs SmarterBoxDIY, can talk you through it. Tell them your phone model and what you've tried.
Get expert helpSmarterBoxDIY is operated by SmarterBox Limited (company no. 16160532). This guide is general information; menus and options vary by manufacturer and software version.
