Why does my phone restart by itself?

It can be frustrating when your phone suddenly restarts or turns off by itself without warning. A spontaneous restart is often a sign that something is wrong with your device. In this article, we’ll explore the top reasons why your phone may be restarting on its own and what you can do to fix the issue.

Software Issues

One of the most common culprits of spontaneous restarts is a software problem. Issues with the operating system, apps, or software updates can all cause stability problems that lead to random reboots or shutdowns. Here are some of the specific software problems that could be the cause:

  • Buggy operating system – Bugs or glitches in the OS can cause it to crash and restart.
  • App conflicts – If two apps are clashing, it can sometimes trigger a reboot.
  • Failing software update – A bad update that didn’t install properly may be trying to repeatedly reboot and re-apply.
  • Full storage – If your phone’s storage is completely full, it can cause software crashes.
  • Too many background apps – Excessive apps running in the background overload the RAM and drain system resources.

If you think a software issue is the cause, there are a few troubleshooting steps you can take:

  • Check for and install any available OS updates
  • Restart your phone in safe mode and see if the problem persists. Safe mode launches your device without any third-party apps running.
  • Try uninstalling recently downloaded apps, especially if the restarts began after installing something new.
  • Clear cached app data which can get corrupted over time.
  • Factory reset your phone if all else fails. This will wipe the OS and software back to factory settings.


One of the most common reasons a phone restarts by itself is overheating. Phones have built-in sensors that monitor temperature. If the internal components get too hot, the device will automatically power down or reboot to prevent damage.

Here are some of the main reasons your phone may be overheating and restarting:

  • Intensive gaming – Playing graphics-heavy 3D games heats up the processor.
  • Charging while using – Charging the battery generates heat, so using the phone intensively while charging makes overheating worse.
  • Poor ventilation – Blocking the phone’s ventilation ports prevents heat dissipation.
  • Direct sun exposure – Leaving your phone in direct sunlight, like on a car dashboard, can overheat the battery.
  • Too many apps/processes – Having too many apps and background processes running burdens the processor.

To prevent overheating restarts, avoid heat-inducing usage while charging, clear background apps, and keep ventilation ports clear. You can also use a phone cooling fan accessory.

Faulty Hardware

While not as common as software issues, faulty hardware can also be the culprit behind spontaneous restarts. Hardware issues that can cause your phone to reboot include:

  • Failing power button – If the power button is damaged or sticking, it may be restarting the phone.
  • Damaged battery – A battery that can’t hold a proper charge will randomly die and restart.
  • Loose internal connections – Components like the memory card or cables loosening inside the phone can cause shut downs.
  • Thermal paste issues – The thermal paste that regulates temperature may be old and ineffective.
  • Faulty RAM – Bad memory (RAM) chips can cause crashes and reboots.

With hardware problems, the only true fix is to have the phone repaired or replaced. But as a temporary workaround, you can try a factory reset or restarting with non-essential hardware like SIM and SD cards removed.

Outdated or Unoptimized Operating System

If you have not updated your phone’s operating system in a long time, being several versions behind the latest release can also lead to stability issues, random crashes, and reboots. That’s because your current OS lacks all the performance improvements and bug fixes of newer versions.

Likewise, if your OS has not been optimized and customized properly, such as after a major update, it can have software conflicts and caching issues that lead to crashes. Taking the time to customize your OS and apps for optimal stable performance can help avoid these scenarios.

To solve OS version or optimization issues:

  • Backup data and perform a full system update to the newest OS version for your device.
  • After updating, customize your OS by disabling unnecessary background processes, setting preferred performance modes for apps, and arranging your home screens.
  • Perform routine maintenance like wiping the cache partition to clear out outdated temporary data.

Issues with RAM

Your phone’s RAM, or random access memory, plays an important role in stable performance. The RAM temporarily stores all the data your phone needs to be running actively. Insufficient or faulty RAM will cause random reboot issues in a few scenarios:

  • Too many apps open – Having too many apps open at once will overload the RAM’s capacity.
  • Memory leak bugs – Bugs that cause RAM to slowly be consumed and not released properly.
  • Failing RAM module – If the physical chip is damaged or loose.
  • Incompatible app – A particular app may not be coded properly to interact with your phone’s RAM and OS.

To identify if RAM issues are the cause:

  • Check apps open and close unused ones to free up RAM.
  • Test by performing a fresh reboot and opening apps one by one until the issue starts.
  • Check for OS and app updates that address memory leak bugs.
  • Have a technician re-seat the RAM or test the module in a different device.

Adding more RAM through expansion modules may also help if your phone allows it.

Malware, Viruses, or Other Security Issues

While not widespread, malware and viruses affecting the system firmware or software can also be a cause of spontaneous shutdowns and reboots. If your phone is restarting frequently along with other strange behavior like distorted screens, repeated pop-ups, or sluggish performance, it may be infected.

Malware or a virus could have been downloaded hidden within infected apps, files, or links. To remove malware:

  • Scan your phone with a trusted anti-virus app to detect and remove infections.
  • Factory reset your device if scans cannot remove the infection.
  • Avoid downloading from unverified sources and links.
  • Install comprehensive mobile security on your phone.

Less common security issues like a faulty encryption module can also cause sudden restarts so malware is not the only possibility.

Proximity or Moisture Sensors

Phones have built-in sensors to detect things like proximity to your face during calls or moisture. If these sensors start malfunctioning, they can mistakenly trigger your phone to power off or restart.

Issues with the proximity and moisture sensors that may cause problematic reboots include:

  • Obstructed sensor – Earwax or debris blocking the proximity sensor.
  • Water damage – Moisture sensors corrupted by water or other liquids.
  • Sensor calibration – Sensor accuracy diminished and needing recalibration.
  • Invalid readings – Nearby objects, magnets, or cold weather causing interference.

To troubleshoot, clean and visually inspect the sensors for any obstruction or water damage. Try recalibrating the sensors through your phone’s service menu if present. Or disable the sensors temporarily to isolate the issue.

Third-Party Accessories

Incompatible or defective third-party accessories can also be the hidden cause of random system crashes and reboots in some cases. Issues with accessories like:

  • Faulty USB cable – A worn or damaged charging cable can cause improper power delivery leading to shutdowns.
  • Incompatible charger – Use of an unsupported wall charger may overheat or overload the device.
  • Defective battery case – Battery cases not properly passing through all signals can confuse the phone.
  • Problematic microSD card – A corrupted or incompatible external memory card.
  • Faulty headset – Wired audio accessories with short circuits or interference.

Isolate if third-party accessories are the issue by testing the phone without them attached. And be sure to buy name brand accessories that specifically support your phone model.

Drops, Spills or Other Physical Damage

Lastly, physical damage from drops, accidents, or liquid spills can often result in device malfunctions like spontaneous reboots. Impact or liquid may damage internal hardware, sensors, module connections, or the battery. Phones restarting randomly after physical damage point to hardware faults rather than software.

With physical damage, repair is likely needed to replace or fix broken components. You may be able to backup data and do a reset as a temporary solution before seeking professional phone repair.

Preventing Random Restarts

While random restarts are frustrating, there are steps you can take to avoid them:

  • Close unused apps and processes to free up system resources.
  • Maintain the latest OS version and all software updates.
  • Avoid overheating by not charging and using intensively at the same time.
  • Only install apps from trusted sources like the Google Play Store.
  • Use reputable brands when buying cables, chargers, batteries and other accessories.
  • Install comprehensive security software to guard against malware.
  • Be careful not to damage your phone through drops, spills or getting it wet.

Catching and addressing restart issues promptly can help prevent wider spread phone malfunctions or permanent glitches.

Cause of Restart How to Fix
Software issue Update OS, uninstall apps, wipe cache partition, factory reset
Overheating Avoid heat sources, add cooling fan, limit resource intensive usage
Hardware failure Replace faulty hardware like battery, power button, RAM module
Outdated OS Perform system update to newest OS version
Insufficient RAM Close background apps, expand RAM if possible
Malware/virus Scan with antivirus apps, factory reset
Sensor issues Recalibrate or replace faulty sensor
Third-party accessory Replace accessory with better quality or OEM version
Physical damage Repair phone and replace damaged components

When to Take Your Phone to a Repair Shop

If you’ve tried the troubleshooting tips outlined but your phone continues randomly restarting, it may be time to take it to a repair shop. Warning signs a professional repair is needed include:

  • Restarting persists after a factory reset
  • Repeated crashes or freeze-ups in addition to reboots
  • Phone feels abnormally hot when restart happens
  • Noticing physical damage like a cracked screen
  • Other major glitches beyond restarting occurring
  • OS update fails to install properly

Repair technicians have the tools and experience to accurately diagnose your phone’s issue whether it be software corruption, hardware failure, or physical damage. Many repair shops offer free diagnostics to tell you what’s wrong before committing to any service. For serious system errors a full reprogramming of the phone’s internal memory may be needed.

When to Back Up Your Data and Replace the Phone

While random restarts are usually repairable, there comes a point when your phone’s problem may be too advanced or widespread to justify the time and cost of repairing an aging device. Signs it’s time to backup your data and upgrade to a new phone include:

  • Phone is 3+ years old
  • Repairs would exceed the phone’s current value
  • Issues are suspected to be due to physical damage
  • Multiple components like battery, screen, ports all having problems
  • OS is no longer supported for updates
  • Crashes, lockups, or glitches in addition to restarts

With phones being used so heavily each day, they have a functional lifespan of typically 3-5 years. If your device is over 3 years old and exhibiting random restarts along with other concerning symptoms, it may have simply reached end of life.


Spontaneous restarts are a common smartphone headache with several possible causes ranging from minor software glitches to serious hardware defects. The good news is randomly restarting phones can often be fixed with software troubleshooting, an OS update, removing apps, or replacing third-party accessories. But in severe cases of hardware damage or aging, professional repair or phone replacement may be the answer.

Use the tips in this article to systematically isolate why your particular phone is restarting itself so you can find the right solution. Catching and resolving random restart problems quickly before they worsen will save you from bigger headaches down the road.

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