Why deleting your things is not enough
Before a phone, tablet or laptop goes to a new owner, you want your photos, messages, passwords and accounts gone from it. Dragging files to the bin, or uninstalling a few apps, does not do that. Data can remain in places you do not see, such as app storage, saved logins, cached files and system backups. Phones also stay linked to your accounts, which can block the next person from using the device.
The reliable approach is a short sequence: back up, sign out, reset, check. Doing it in that order avoids most problems.
What a factory reset does
A factory reset returns the device to the state it was in when it left the factory, from a software point of view. It removes your accounts, installed apps, settings and personal files, and reinstalls a clean copy of the operating system or leaves the device ready to be set up again.
It does not change the hardware, and it is not an undo for physical damage. It also does not touch things stored elsewhere, such as your online accounts, cloud backups, a memory card you can remove, or a SIM card. Those need separate attention.
Names for the feature vary: “reset”, “erase all content and settings”, “reset this PC”, or “wipe data”. Look for these in settings. Computers sometimes offer a choice between keeping your files and removing everything. For selling, you want the option that removes everything.
Why encryption matters
The question people reasonably ask is whether wiped data can ever be recovered. The answer depends largely on encryption, which is covered in more depth in our article on device encryption.
Most modern phones encrypt their storage by default. The data on the storage chip is scrambled with a secret key that is protected by your passcode and by special hardware. When a reset is carried out on an encrypted device, the key is usually destroyed, which means that what remains on the chip is unreadable noise. That is generally a quick and strong way to erase data.
On devices that do not encrypt, such as some older phones or computers, deleting files may leave the underlying data in place until it is overwritten, and special software could potentially recover it. In that case:
- Turn encryption on first if the device offers it, then reset. This way, the data is scrambled before it is erased.
- On computers, use the built-in drive encryption feature and the manufacturer’s secure erase or reset option.
- Spinning hard disks and solid-state drives behave differently when erased, so use the manufacturer’s recommended method.
No method can promise that nothing could ever be recovered by a determined expert, but encryption plus a reset is a sound approach for ordinary use.
Before you reset: the checklist
1. Back up what you want to keep. Copy photos, documents and chat history to a computer, an external drive or a cloud storage service. Check the backup contains what you expect before moving on. Our backup strategy article explains why more than one copy is wise.
2. Move what is tied to the device. Authenticator apps, mobile wallets, messaging apps and banking apps may be linked to this particular phone. Set them up on the new device first, using each service’s own transfer or recovery process. Locking yourself out of an account is the most common painful mistake, and it is worth confirming that two-factor authentication works on the new device before wiping the old one.
3. Sign out of the accounts, starting with the important ones.
- The phone’s main account (such as the account tied to the app store and device-finding feature). This matters most. On many phones, a locator or activation lock keeps the device tied to your account even after a reset, so the next owner cannot use it, and you may be contacted later by a frustrated buyer. Turn the tracking and lock features off and remove the device from your account list.
- Messaging apps and email. Sign out, and where an app offers it, unlink the device from your account in its settings.
- Cloud, social and shopping accounts that store logged-in sessions.
- Banking, payment and wallet apps. Remove cards from mobile wallets.
- Streaming and game services, which often limit how many devices can be signed in.
4. Unpair accessories. Smartwatches, earbuds and trackers that are paired with the device should be removed. A watch usually has its own reset.
5. Take out what is physical. Remove the SIM card, and any memory card. If your phone uses an eSIM, delete the plan from the device through settings, or contact your carrier if you are unsure.
6. Check your family sharing and other groups. If the device belongs to a family sharing group, remove it so the next owner does not have access to shared purchases.
Doing the reset
- Plug the device in or make sure the battery is well charged, since an interrupted reset can cause problems.
- Open the reset option in settings and confirm the prompt, entering your passcode if asked.
- Wait for it to complete. It can take several minutes, and the device will restart.
- Check the result. A device that is correctly wiped shows the first-time setup screen, like a new one. Stop there. Do not sign in with your own account.
- If the setup screen asks for the previous owner’s account, the lock was not removed. In that case, you may need to turn the device-finding feature off using your online account, and then reset again.
Some people want an extra layer of caution on an old phone. A simple way is to sign out, reset, and then confirm in your online account settings that the device no longer appears in your device list.
Special cases
- Broken devices that will not turn on. They cannot be reset. Sign out of your accounts online where possible, and use a recycler who will handle data securely, as explained in our article on recycling and repair.
- Work or school devices. These may be managed by an organisation and are not yours to wipe or sell. Ask the administrator.
- Laptops. Besides the reset, sign out of your operating system account, deauthorise licensed software and deactivate any paid programs.
- Smart home devices and cameras. These need removing from your account in the companion app and resetting by the manufacturer’s method.
After you hand it over
Change passwords for any account you are concerned about, particularly if you could not complete every step. Watch for unfamiliar sign-in alerts. If you think you may have missed something, the remote steps used for a lost phone, such as signing the device out and removing it from your accounts, work in this situation too.
A careful ten minutes beforehand protects your privacy and makes the sale smoother for everyone.