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On a Samsung Galaxy S21, “hard reset” usually means a factory data reset: it erases personal data stored on the phone. If you can use Settings, go to Settings > General management > Reset > Factory data reset, review the screen, and confirm only when you are ready. Back up anything you need and make sure you know the Google and Samsung account credentials that may be required afterward.
What “hard reset” means on a Galaxy S21
People use “hard reset” to mean different things. A restart simply powers the phone off and back on; resetting all settings restores configuration defaults while retaining apps and personal data; a factory data reset erases personal data from the phone. Samsung Support describes a factory data reset as restoring factory settings and removing all personal data. The Recovery Mode procedure is another way to initiate that same kind of wipe when Settings is unavailable.
| Option | What happens | When it fits |
|---|---|---|
| Restart or power cycle | Refreshes the phone without deleting saved data, according to Samsung’s general reset guidance. | Try for a temporary freeze or routine troubleshooting. |
| Reset all settings | Returns settings to defaults without deleting apps or personal data, according to Samsung. | Use when a configuration issue is suspected and you want to preserve data. |
| Factory data reset in Settings | Returns the phone to factory settings and removes personal data stored on it. | Use when you intend to erase the device and can operate Settings. |
| Recovery Mode factory reset | Uses the hardware buttons and Recovery menu to wipe data. | Use when normal Settings access is unavailable. |
| SmartThings Find erasure | Can erase data remotely if the service and required settings were configured beforehand and the device meets its prerequisites. | Consider only when the phone is inaccessible and the remote service was set up in advance. |
Samsung notes that menu names and layouts can vary by model and software version, so follow the prompts shown on your S21. Samsung’s US factory-reset instructions document the Settings route and reset choices.
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- Back up what you want to keep. Copy or sync photos, videos, documents, and other important information. Samsung warns that personal information may not be recoverable after a factory reset.
- Check encrypted microSD cards. Samsung advises decrypting an encrypted microSD card before resetting; otherwise, the device may not be able to read it afterward.
- Prepare your account credentials. A signed-in Samsung account may require its password to complete the reset. Google Factory Reset Protection (FRP) may require verification of the Google account previously registered on the phone after a reset.
- If transferring the phone, plan for identity checks. Make sure the legitimate owner can complete any requested account verification. Samsung says Android 9 and later may also offer the screen-lock method previously configured on the device.
- For the documented Settings flow, connect to a network. Samsung’s US guide says a network connection is needed to log out of a Samsung account in the flow it describes.
FRP is a theft-protection measure, not a step to bypass. If the rightful owner cannot verify the account, recover that account or contact Samsung Support.
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How do I factory reset a Galaxy S21 from Settings?
- Back up needed data and confirm you know the relevant Google and Samsung account credentials.
- Open Settings > General management > Reset > Factory data reset.
- Review the information on the factory-reset screen, including what will be removed.
- Tap Reset, then Delete all, if those are the labels shown on your S21. Enter your screen-lock credentials if prompted; a Samsung account password may also be requested.
- Let the phone complete the reset and follow its on-screen setup instructions. If a previously registered Google account is requested, verify with that account.
Do not confirm the final erase prompt unless you intend to remove personal data. Software versions may present different wording or screens.
How do I reset my Samsung phone if I’m locked out?
If Settings cannot be operated normally, Samsung’s French Recovery Mode guidance includes the Galaxy S21 among models without a physical Home key. It describes holding Volume Up together with the side key until the phone vibrates and the Samsung logo appears, then using the Recovery menu’s Wipe data/factory reset option. Confirm the wipe in the menu and choose the system reboot option afterward.
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Button timing and screen behavior can differ across firmware variants; the regional instructions are not a guarantee that every S21 will show identical prompts. If your screen or buttons behave differently, stop and consult Samsung France’s device-reset guidance or Samsung Support for your model and region. A Recovery Mode wipe is still a factory reset, so the data-loss and account-verification cautions apply.
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Can I erase a Galaxy S21 remotely?
Samsung lists remote data erasure through SmartThings Find, but it depends on setup and connectivity before the phone becomes inaccessible. Samsung says the device must be on, have the Samsung account and Mobile Find setting configured, allow Google location access, and have internet access. If those conditions were not met beforehand, the remote erase option may not be available.
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Samsung’s general reset guidance, updated 25 June 2026, illustrates settings on a Galaxy S24+ running Android 15 and One UI 7; those screenshots are not S21-specific. Use the labels and prompts on your own phone when available.
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