Samsung phone keeps restarting? 9 ways to stop it

A Galaxy that restarts by itself can mean anything from a harmless scheduled restart to a failing battery. The trick is to rule out the simple causes in the right order, so you do not erase your phone when a setting was to blame. The fixes below start with the ones that take seconds and end with repair options.

Why Samsung phones restart on their own

• Auto restart: a scheduled restart built into One UI.
• A buggy update or app: common in the days after a One UI update.
• Low storage: the system runs out of room for temporary files.
• Heat: the phone shuts down to protect the battery and chip.
• A worn battery: it cannot supply peak power, especially when cold or low.
• Charging hardware or water: a bad cable, a damaged port or moisture.
• Physical damage: a drop can loosen a connector or damage the board.

It also helps to know which kind of restart you have. Random restarts happen while the phone is otherwise working. A restart loop means the phone never gets past the Samsung logo. If yours is looping, see what to do when a Samsung is stuck on the logo.

Is it restarting on purpose?

Many Galaxy phones have a feature called Auto restart that restarts the phone on a schedule, usually overnight, or when the phone decides it needs it. If your phone restarts at the same time each day, this is the reason, and nothing is wrong.

How to stop a Samsung phone from restarting

Restarts after a One UI update

Major One UI updates optimize apps in the background for a day or two, and some apps misbehave until they are updated for the new version. Leave the phone charging overnight on Wi-Fi, update every app, and check for a follow-up software update a week or two later, since Samsung often patches early bugs quickly. On some Galaxy models, recovery mode also offers Wipe cache partition, which clears temporary system files without touching your data. If your model has it, it is worth trying before a reset.

Restarts when hot, cold or low on battery

If restarts happen during gaming, navigation or charging in a hot car, the phone is protecting itself from heat. Remove the case and let it cool. If they happen in cold weather or below about 20%, the battery is likely worn and cannot deliver enough power. The battery test in Samsung Members helps confirm it, and a battery replacement usually ends the restarts completely. See also Samsung charging problems.

Two quick hardware tests

• Take out the SIM card: a damaged SIM or tray can, rarely, cause restarts. Remove it and use the phone on Wi-Fi for a day. If the restarts stop, ask your carrier for a new SIM or an eSIM.
• Remove accessories: unplug power banks, car chargers and USB accessories, and take off cases with batteries or metal plates. Use the phone bare for a day and see if anything changes.

Keep a quick note of when each restart happens: charging, gaming, in the car, at a certain battery level or at random. That simple pattern usually points to the real cause much faster than trying fixes blindly, and it is exactly what a repair technician will ask you.

Could it be malware?

Rarely, but it happens, usually with apps installed from outside the Play Store or Galaxy Store. Signs include pop-up ads outside apps, new apps you did not install, and restarts that stop in Safe mode. Remove anything suspicious in Safe mode and run a scan with Google Play Protect. See how to scan an Android phone for malware.

Keep it from happening again

• Install One UI and app updates, but give big updates a day to settle before judging them.
• Keep at least 10% of storage free.
• Install apps only from the Play Store or Galaxy Store.
• Avoid heavy gaming while fast charging, and keep the phone out of hot cars.
• Leave Auto restart on if you like it; just set it to a time when you are asleep and the phone is charging, so it never surprises you during the day.

Back up before anything drastic

A phone that restarts randomly can fail completely without warning. As soon as it stays on long enough, back up photos, contacts and messages with Samsung Cloud, Google or Smart Switch on a computer. See how to back up an Android phone. Do this before a factory reset or a repair.

Getting it repaired

If the phone restarts even in Safe mode and after a reset, it is a hardware fault. Samsung service centers and Samsung authorized repair partners can run full diagnostics. Before you hand it over, turn on Maintenance mode in Settings › Battery and device care (or Device care) › Maintenance mode, if your phone has it. It hides your personal data from the technician while leaving the phone usable for testing. If you have Samsung Care+ or carrier insurance, check your coverage first.

A battery replacement is the cheapest common fix, and on a phone that still gets updates it is usually money well spent, since a fresh battery also brings back full battery life. If the fault is on the main board of an older Galaxy, the repair can approach the cost of a new phone, so compare quotes with the phone’s trade-in value before deciding. If the problem began after the phone got wet, see what to do when your phone gets wet.