Smartphone Samsung Galaxy M21, despite its popularity and reliability, may become unstable over time. Accumulated software junk, conflicting applications, or failed system updates often lead to slow performance, freezes, and rapid battery drain. In such situations, the only effective solution is to completely return the device to its original state, which eliminates all software errors.
The full reset operation, known as Hard Reset or Factory Reset, deletes absolutely all data from the gadget’s internal memory. This includes contacts, photos, music, installed applications and personal system settings. Therefore, before starting the procedure, it is critical to create a backup copy of all valuable information to avoid its irreversible loss.
In this guide, we will look in detail at all available methods for restoring factory settings on a model M21. We will look at both the standard method through the settings menu and the emergency method using physical buttons, which is necessary if the phone does not turn on or is locked. Answers will also be given to questions about protecting your Google account and the features of working with the updated shell One UI.
Preparing the device for a complete data reset
Before initiating the cleaning process, you must perform a number of preparatory steps that guarantee the successful completion of the operation. The very first and most important step is to synchronize your important data with cloud storage or transfer it to an external storage device such as an SD card or computer. Make sure your contacts are saved in your Google account and your photos are uploaded to Google Photos or Samsung Cloud.
The second critical point concerns the battery level. The process of formatting internal memory and reinstalling system files is energy-consuming. If the battery dies in the middle of the procedure, this can damage the system partitions and turn the smartphone into a “brick”. Charge the device at least to 60-70%, or better yet, connect it to the charger for the duration of the entire operation.
⚠️ Attention: Make sure you remember the password for your Google account. After the reset, the system will require you to enter the account information that was previously synchronized with the device, as an anti-theft measure (FRP Lock).
It is also recommended to remove the memory card microSDif it is installed in the slot. Although modern versions of Android usually ask for confirmation before formatting an external drive, physically removing the card completely eliminates the risk of accidentally deleting your archives and media files stored on it.
☑️ Checklist before resetting
Method 1: Reset through the Android settings menu
This is the most secure and preferred method and is suitable for devices that are in working order and have access to the home screen. The shell interface One UI from Samsung is intuitive, and all the necessary items are located in a logical sequence. To begin, unlock the screen and find the application icon Settings, which usually looks like a gear.
In the menu that opens, scroll down the list to the item General settings (in some firmware versions it may be called simply System or be in section Device maintenance). Inside this section you need to find the option Reset. Clicking on this item will open a new window with a list of available recovery options, among which we are interested Reset data.
The system will display a warning about what data will be deleted. Carefully review the list, which usually includes accounts, system settings, downloaded applications and media files. To confirm the action, you will need to enter the current PIN code, pattern or screen unlock password, as well as the password for your Samsung account, if activated.
Before clicking the final “Delete All” button, double-check that all important files have been copied to your computer or to the cloud. It will be impossible to cancel this process once it has started.
After confirmation, the smartphone will automatically reboot and begin the cleaning process. The screen may display a logo Samsung or animation of the Android robot. Do not touch the device at this moment: the process may take from 5 to 15 minutes depending on the amount of memory used. Upon completion, the phone will turn on as new, prompting you to select a language and connect to Wi-Fi.
Method 2: Hard Reset via Recovery Mode (buttons)
If the smartphone is frozen, does not respond to touches, the pattern key is forgotten or the device does not boot to the main screen, you must use a hard reset through the recovery menu (Recovery Mode). This method does not require access to the operating system and is performed solely using physical buttons. Please note that on new versions of Android, entering this menu often requires connecting a USB cable.
To enter recovery mode on Samsung M21 follow the following sequence of steps. First, turn off the device completely. If the phone freezes and does not turn off in the usual way, press the Volume down and Power buttons simultaneously for 7-10 seconds until the screen goes completely dark.
1. Connect the switched off phone with a USB cable to your computer or laptop.2. Press the “Volume Up” and “Power” buttons simultaneously.
3. Hold them until the Samsung logo appears, then release the "Power" button, but continue to hold "Volume Up".
4. When the Recovery menu appears (black screen with text), release all buttons.
In the recovery menu, navigation is carried out with the volume buttons (up/down), and the selection is confirmed with the power button. You need to find the item Wipe data/factory reset. Be extremely careful: selecting the item Wipe cache partition will clear only temporary files, but will not reset the settings, so make sure that data reset is selected.
⚠️ Attention: On some models with the updated version of Android 11 and higher, entering Recovery without a USB cable connected to the PC may be blocked. If the menu does not appear, be sure to use the cable.
After selecting the reset item, the system will ask for additional confirmation, usually in the form of a list of options No and one Yes or Factory data reset. Select confirmation. The process will go quickly, and a message will appear at the bottom of the screen Data wipe complete. Then select Reboot system now to reboot.
What to do if the Recovery menu does not appear?
If the button combination does not work, try connecting the phone to a wall charger instead of the computer. Also make sure that the buttons are not stuck and press with a clear click. In rare cases, several attempts are required with different_timing_presses.
Features of FRP and Google account protection
Modern Samsung devices are equipped with a security system FRP (Factory Reset Protection). This feature is designed to protect the owner's data in case of loss or theft of the smartphone. The gist of it is that after performing a factory reset, the device is locked until the user enters the login and password for the Google account that was synced with the phone before the reset.
This means that if you reset your own phone, but do not remember the Gmail password, you will not be able to use it after the reboot. The system will require authorization during the initial setup stage. It is impossible to bypass this protection in legal ways without entering correct data, which is an important precaution.
| Situation | Action before reset | Risk of blocking |
|---|---|---|
| Selling a phone | Delete Google account in settings | High (the buyer will not enable it) |
| Forgotten screen password | Remember Gmail password | High (requires entering after reset) |
| My phone, I remember everything | Nothing required | Missing (enter the password during setup) |
| Found phone | No access to account | Critical (the phone will become useless) |
If you plan to sell or give away Samsung M21, it is strongly recommended to delete your Google account manually before resetting. To do this, go to Settings → Accounts and archiving → Account management, select your Google account and click Delete account. Only then can you safely perform a data reset.
Data recovery and initial setup
After successful completion of the reset and reboot procedure The device greets you with a language selection screen. This stage is familiar to everyone who has turned on a new smartphone at least once. Select Russian language, connect to an available Wi-Fi network to activate the device and check for security updates.
The system will offer to restore data from a backup copy. If you have previously created a backup in your Google or Samsung Cloud account, you will be able to select a restore point. This will automatically restore contacts, call history, alarm settings, and even the location of icons on the desktop. However, the applications will have to be downloaded again from the store Google Play.
During the setup process, the wizard will prompt you to set a lock screen. Create a strong PIN or pattern, but be sure to write it down in a safe place. Also at this stage, biometric data is configured: fingerprint and facial recognition. For Samsung M21 the fingerprint scanner is located on the side of the case, combined with the power button.
Restoring from a cloud backup saves hours of time by returning settings and contacts automatically, but do not forget to check that important files were actually uploaded to the cloud before the reset.
Possible problems and solutions solutions
Despite the simplicity of the procedure, users may encounter a number of technical difficulties. One of the common problems is getting stuck on the logo Samsung after a reset (bootloop). This may occur due to corrupted system files or a hardware conflict. In this case, you need to re-enter Recovery Mode and try to clear the partition Cache (Wipe cache partition), if this is possible in your software version.
Another situation is that the phone requires unlocking through an account that you do not remember. In this case, the only legal solution is to restore access to your Google account through the forgotten password procedure on any other device (computer or tablet). Using third-party FRP bypass software may be unsafe and may void your warranty.
If your phone quickly discharges or gets hot after resetting, give it time. In the first hours after installation, the system indexes files and optimizes applications in the background. This is normal behavior. If the problem persists for more than a day, perhaps one of the restored applications is causing the conflict and should be deleted.
⚠️ Attention: The interface and menu item names may vary slightly depending on the version of Android (10, 11, 12) and the version of the One UI shell. If you do not find an exact match, look for synonyms or similar icons.
Frequently asked questions (FAQ)
Will information be deleted from the SD memory card when resetting?
By default, resetting to factory settings affects only the internal memory of the smartphone. The data on the memory card microSD remains intact. However, if during the reset process you specifically select the option to format the external drive (which the system usually asks for separately), then the data will be deleted. For complete safety, it is better to remove the card before starting the procedure.
How long does it take to completely reset a Samsung M21?
The data clearing process itself usually takes from 5 to 10 minutes. However, subsequent initial setup, indexing the system and restoring applications from a backup can take from 30 minutes to several hours depending on the Internet speed and the amount of data being restored.
What to do if the phone asks for a password from the previous owner?
This is FRP protection. The phone is locked until you enter the Google account that was installed on it before the reset. If you bought the phone secondhand and do not know this account, you need to contact the seller to obtain data or proof of purchase to contact the Samsung service center.
Is it possible to interrupt the reset if it hangs in one place for a long time?
It is strictly not recommended to forcefully interrupt the process if the progress indicator moves, even slowly. Forcing a reboot while writing system files may cause software corruption. The wait is up to 20-30 minutes. If the phone is frozen for more than an hour, then a flashing via a computer will be required.