6 reasons your phone keeps restarting and how to stop it

A constant restart loop makes a phone impossible to use. If your phone keeps flashing its startup logo, the cause is usually a software glitch or failing hardware. Testing these causes in order will help you fix the issue and get your device working again.

1. Check for a pending or failed software update

Your phone needs a complete and stable operating system to run smoothly. A software update that stalls halfway through can leave the device restarting over and over. This happens when the phone tries to load the new system, finds an error and tries again. You get stuck watching the startup screen flash repeatedly.

You can fix this by forcing the update to finish. Plug the phone into a wall charger first, since a battery that dies during an update causes even more problems. Connect the device to a stable home wifi network to avoid burning through your cellular data. Go into the settings menu to look for any downloads waiting for approval.

On Pixel phones, Google says to check Settings, then System, then Software update, and install any available update. Other Android phones use similar menus to manage their downloads. Let the phone finish the installation without touching the screen or the buttons. The device will restart one last time when the update completes.

2. Free up storage when it is nearly full

Operating systems need empty space to swap files and process data efficiently. A phone with a packed hard drive can run into problems, including crashes and restarts. The system freezes when it tries to open an app and finds zero free memory.

Google says phone problems can occur when less than 10 percent of storage is free. You can check your available space in the main settings menu. Look for the storage section to see a clear breakdown of what takes up the most room. Downloaded videos and offline maps usually sit at the top of that list.

Delete large video files and clear out podcast episodes you already heard. Remove games you no longer play. Moving your photo library to a cloud service will also open up a lot of space quickly. Keep checking the storage menu until you have more than 10 percent of storage free to give the phone room to work.

3. Find a misbehaving app with safe mode

A single poorly written application can drag down an entire operating system. Apps running in the background sometimes conflict with core system processes, draining memory fast. The phone eventually runs out of computing power and forces a reboot to protect itself.

You can test for bad software by booting the device in safe mode. Google says safe mode temporarily turns off all downloaded apps, so restarts that stop in safe mode point to an app. On many Android phones you reach safe mode by pressing and holding the power off icon on the screen, so check your maker's steps. Some phones ask you to hold the volume down button while the device starts up.

If the phone runs perfectly in safe mode, a downloaded app is the likely cause. Restart the phone normally to turn safe mode off, then delete your most recent downloads one by one. Wait to see if the random restarts stop after each removal. Once you find the bad app, leave it uninstalled.

4. Rule out heat and a worn battery

Batteries degrade over time and lose their ability to deliver peak voltage. When a worn battery cannot supply enough power for a demanding task, the phone shuts down and restarts. You might notice the device dies quickly even when the screen shows a partial charge. Extreme heat also triggers an automatic shutdown to prevent permanent damage to the processor.

Keep the phone out of direct sunlight and away from hot car dashboards. If the device feels hot to the touch, leave it on a cool indoor table until it feels normal. Learning good charging habits helps prevent early battery failure. Letting a phone cool down completely might solve the restart loop on its own.

A completely dead battery might trap a phone in a continuous loop as it tries and fails to boot. Apple says an iPhone that will not turn on should be charged for one hour before you try again. Use a standard wall outlet and a good cable to make sure the device gets a steady flow of power. Avoid plugging it into a weak computer port.

5. Check the power button and a tight case

Physical buttons get stuck when pocket lint and dirt build up in the tiny gaps around them. A jammed power button can keep sending a signal that shuts down or reboots the device. The phone assumes you are holding the button down on purpose.

Google suggests removing any case or external battery pack when a phone keeps restarting. A tight plastic case can easily pinch the power button without you noticing. Take the phone out of its case and wipe the edges with a clean dry cloth. Press the power button a few times to make sure it clicks firmly and springs right back out.

Sometimes a simple hard reset clears a temporary physical glitch that mimics a stuck button. Apple says to force restart a Face ID iPhone by pressing volume up, then volume down, then holding the side button until the logo appears. For an Android phone, check your maker's support page for the force restart steps.

6. Back up and factory reset as the last step

Software problems sometimes dig too deep for a simple menu fix. A corrupted operating system file may keep triggering restarts. It is a reasonable last software step when safe mode and storage clearing fail to fix the loop.

A factory reset erases everything and returns the software to the exact way it left the assembly line. This process deletes your personal files and app data permanently. You must back up everything you want to keep to a computer or a cloud account first. Read about what to do before you factory reset to keep your files safe.

Go to the system settings and find the reset options. Choose the factory data reset and confirm your choice. The phone will take some time to erase the drive and install a fresh copy of the operating system. You will then have to log in and download your apps all over again.

When the restart loop points to hardware

A phone that keeps restarting after a full factory reset may have a hardware fault. Software resets cannot fix damaged hardware.

Water damage can cause random restarts, and so can a hard drop that damages internal parts.

You cannot fix motherboard damage at the kitchen counter. A local repair shop can test the battery and the internal components safely. They will tell you if a repair costs less than buying a replacement device.