Back up what you want to keep, note the accounts you will need, remove the device from its app and cloud account, then run the built-in factory reset, often called erase all content and settings. Do not keep personal files when offered. A reset removes data for ordinary purposes, not against a determined expert.
Before you reset
The NCSC lists steps for phones that apply in spirit to other devices.
- Back up any data you want to keep, because the reset removes personal data.
- Note your online accounts and logins, especially ones you reach without typing a password.
- Plan for the smart devices your phone controls, such as cameras or thermostats, and set up another way to manage them.
- Check that SMS verification works on another device before you erase a phone, since it may confirm logins.
Do the reset
Use the device's built-in reset. The name varies: erase all content and settings, or factory reset. The NCSC says to check the manufacturer's website for the exact name. When offered the option to keep personal files, decline it.
For smart home devices, also remove the device from the companion app or account. A device that is reset but still listed in your account can cause confusion for the next owner and leave you linked to it.
Other devices need their own reset
The NCSC notes that other devices such as smart TVs, fitness trackers, speakers and games consoles need their own manufacturer reset. Find the steps on the maker's site. Some require a button press sequence rather than a menu.
What a reset does not guarantee
The NCSC says a determined expert with specialist tools may still recover some data from a device. For data that must never be recoverable, follow its secure sanitisation guidance, and consider destroying the device through a proper disposal route instead of selling it.
A short written record
Keep a note of what you did: the device, the date, and that you removed it from your account. If something goes wrong later you can show your steps.
Special cases worth a minute
Some devices keep a separate pairing with a controller, such as a speaker paired with a hub or a camera paired with a base station. Remove those pairings in the controller first, then reset. If you reset the device first, you may be left with an orphan entry in the app that you cannot delete without the device.
Shared accounts need care. If a family member also uses the device through their own login, tell them before you remove it, and check whether the device appears in their app too.
If the device used a memory card for recordings, remove the card. A factory reset may not touch removable storage, so check the manual for what it erases and either wipe the card on a computer or keep it.
If you are the buyer
Do your own reset on arrival, and check the update support first. The companion post on buying second-hand devices covers that.
Quick check
Is deleting my account on the device enough?
No. Run the full factory reset and also remove the device from the app or cloud account.
Should I reset a device that is broken?
If it still powers on, try. If it will not, consider whether disposal through a recycling route is safer than selling it.
Sources
Last reviewed: 19 October 2026.
