A factory reset erases everything stored locally on an Android phone. That is the point — it is how you fix a broken phone, prepare it for sale, or hand it to someone else. But a reset is only safe if everything important already lives somewhere else, and “somewhere else” has to mean a backup you have actually verified, not a setting you assume is on.

The most common losses after a reset are not photos — those usually survive through Google Photos. They are the things a standard backup does not cover: two-factor codes, WhatsApp history, downloads, local files, and authenticator access. This guide walks through the full checklist in order: the main backup, the separate photo backup, the app-by-app checks, the accounts you will need afterward, and the final steps before you press reset.

Step 1: Run the main backup — and verify it

Google’s backup is the backbone. It covers apps and app data, call history, contacts, device settings, and SMS and MMS messages. It does not cover photos and videos — those back up through Google Photos separately — and it does not cover app-specific local data that apps choose not to back up.

1. Go to Settings > Google > All services > Backup and restore > Backup. The switch is labelled Backup by Google One.
2. Confirm it is on, then tap Back up now.
3. Wait. Google says a backup can take up to 24 hours, and a restore can take up to 24 hours too. Run it on Wi-Fi and power, and do not reset the phone until it reports a recent completion time.
4. Verify it from another device: open Google One in a browser, go to the Backup section, and confirm your phone and a recent timestamp are listed.

Two catches to know. First, if you turn off device backups, the stored backups are deleted. Second, if a device is not used for 57 days, Google deletes the device backup — that does not affect what is already in Google Photos, but it means an old backup you are counting on may not be there. Also, you cannot restore a backup from a higher Android version to a lower one, so if the new phone runs an older Android version than the old one, the restore will not work.

Step 2: Back up photos and videos separately

Open Google Photos and confirm backup is on and that it reports “Backup complete.” If it is still uploading, wait — a large library on a slow connection can take hours. Photos and videos are the one category where “the backup setting is on” is not enough; you need the app to say it has finished.

For anything irreplaceable, copy it to a PC over USB as well. A second copy costs a few minutes and protects you if the cloud backup turns out to be incomplete. Check the copy from the PC afterward — open a few photos at full size — before you reset the phone.

If your phone is short on space and the backup is stalling, free space first using our Android storage guide.

Step 3: Check the data that lives outside the main backup

Several categories need separate action. Go through them one by one:

• WhatsApp: open WhatsApp, go to Settings > Chats > Chat backup, and run a backup to Google Drive now. Confirm the date shown is today. Without this, your chat history does not come back after the reset.
• Authenticator apps: this is the most important check on this list. Google Authenticator now syncs verification codes to your Google account — open the app and confirm the cloud-sync symbol is active on your profile icon. If you previously chose “Use Authenticator without an account,” your codes exist only on the device and a reset erases them permanently. Either enable cloud sync or use Menu > Transfer accounts > Export accounts to move them to a second device first. Other authenticator apps have their own backup systems — Authy and Microsoft Authenticator each have one — so verify each is enabled before you reset.
• Passkeys: passkeys can sync through a platform account or remain device-bound depending on how they were created. Check each critical service’s security settings from another signed-in device before you erase the phone.
• Downloads and local files: files in the Downloads folder, documents saved by apps, voice recordings, and anything stored on the phone rather than in the cloud are not covered by the Google backup. Copy them to a PC or upload them to Google Drive.
• microSD card: if your phone has one, decide whether to keep it or wipe it. An encrypted microSD card must be decrypted before a reset, or its contents become unreadable.
• SIM and eSIM: know whether the phone uses a physical SIM or an eSIM. If you are keeping the phone, leave the eSIM in place; if you are selling it, note whether the reset screen offers an “Erase downloaded SIMs” option and choose deliberately.
• Work profiles and VPN certificates: a work profile or device-management enrolment may require your administrator to remove it. Ask before resetting.

Step 4: Confirm the accounts you will need afterward

Write down the Google account email address on the phone and make sure you know its password. Confirm that its recovery phone number and email still work. If this phone receives the only two-factor codes you need to sign in to that account, create another recovery path first — a second phone, a set of printed recovery codes kept somewhere safe that is not the phone itself.

If you changed your Google password in the last 24 hours, Google says to wait a day before resetting. A recent password change can trigger a sign-in challenge delay after the reset, which is exactly when you least want one.

Step 5: Remove accounts before you reset

This step matters most when the phone is leaving your hands, but it is good practice in every case. A reset that does not come from the Settings app can trigger Factory Reset Protection (FRP) — the phone then asks for the Google account that was on it before it will let anyone set it up, and a buyer who cannot sign in has a bricked phone.

1. Remove your Google account in Settings > Passwords & accounts (on a Samsung, Settings > Accounts and backup > Manage accounts). Tap the account, then Remove account, and confirm.
2. Sign out of your Samsung account too, if you have one.
3. If you are selling or trading in the phone, also remove it from your Google account’s device list and sign out of any banking or payment apps.

Then reset from Settings, not from Recovery Mode: on a Pixel, Settings > System > Reset options > Erase all data (factory reset); on a Galaxy, Settings > General management > Reset > Factory data reset. Resetting from Settings after removing the accounts clears the FRP lock cleanly. Charge the phone to at least 70% first — Google says a reset can take up to an hour.

Step 6: After the reset

When the phone restarts, sign in with the same Google account and choose to restore from your Google backup when setup offers it. Expect the restore to take time — apps download one by one, and Google says a restore can take up to 24 hours. Check the items from Step 3 individually: WhatsApp history, photos, authenticator codes, and any local files you copied to a PC. If something is missing, it is far easier to fix while the old backup and the PC copy still exist than after you have reused or sold the phone.

If you are switching platforms rather than resetting for repair, our Android to iPhone transfer guide covers the official Move to iOS route and what it does and does not carry across.

The quick checklist

• Google One backup run and verified, with a recent timestamp
• Google Photos reports “Backup complete”
• WhatsApp backed up to Google Drive today
• Authenticator codes synced or exported to a second device
• Downloads and local files copied to a PC or Drive
• Google and Samsung accounts removed (for sale or trade-in)
• Google password known, recovery options working, no password change in the last 24 hours
• Phone charged to at least 70%
• Reset from Settings, not Recovery Mode

The bottom line

A factory reset is safe when the backup is real and verified. Run the Google One backup, confirm Google Photos has finished, and then handle the exceptions one by one — WhatsApp, authenticator codes, downloads, and local files. Remove the accounts before you reset if the phone is leaving your hands, and reset from Settings so Factory Reset Protection does not lock the next owner out. Do not press reset until every item on the checklist is checked.