If your iPhone is restarting again and again for no reason, restarting while charging or stuck in a restart loop, you can find below the troubleshooting steps to fix this problem.
iPhone Restarting Randomly
While the problem of iPhone Restarting randomly has mostly been reported by owners of older devices, this issue can also occur on newer devices.
The reason for iPhone Restarting can range from minor software glitches, malfunctioning apps and corrupted software to hardware related problems.
1. iPhone Keeps Restarting While Charging
If iPhone is Restarting only while charging, the problem is most likely due to broken or faulty charging cable or due to lint/debris being stuck in the charging port.
1. Inspect the Charging Port and Head Phone Jack on your iPhone. If required, clean the Charging Port and Headphone Jack using a toothpick.
While cleaning, make sure that you take all the care and precautions to avoid damaging the charging port and the headphone jack.
2. Inspect the Charging cable to see if it is broken or damaged.
Even if the cable shows no signs of damage, it is possible that it has become faulty. To confirm, use a New or another charging cable to charge your iPhone and see if the problem still occurs.
2. iPhone Restarting Randomly or Stuck in Restart Loop
If iPhone is Restarting Randomly, the problem could be due to various reasons, ranging from incompatible Apps, corrupted system files to hardware related issues.
As long as the problem is not hardware related, it can be fixed using troubleshooting steps as provided below.
1. Remove and Inspect SIM Card
A faulty or improperly inserted SIM Card can make iPhone to be stuck in a restart loop or restart randomly.
1. Shut down iPhone and remove the SIM Card from your device. After removing SIM Card, restart iPhone to see if the problem is gone.
2. Next, put SIM Card back into iPhone and see if the problem returns back.
If the problem returns back, it is most likely that the SIM Card on your iPhone has become defective or damaged. Replacing the SIM Card with a new one should fix the problem.
2. Force Restart iPhone
Follow the steps below (As applicable for the model of your iPhone) to Force Restart iPhone.
iPhone 8 and above: Press and release Volume Up > Volume Down > and then press and hold the Side button (ON/OFF), until Apple logo appears.
iPhone 7/7 Plus: Press and hold Volume Down + Power (ON/OFF) buttons, until you see Apple logo.
iPhone 6 and below: Press and hold Home + Power (ON/OFF) buttons, until you see your iPhone starting with Apple logo.
3. Install Updates
Make sure that you are using the latest version of iOS on your iPhone.
1. Go to Settings > General > Software Update.
2. On the next screen, wait for iPhone to check for updates and tap on Download and Install link (If an Update is available).
After installing the update, restart your device to see if the problem is now fixed.
4. Update Apps
The problem of iPhone Restarting randomly can be caused by outdated or incompatible apps installed on your device.
1. Open the App Store on your iPhone and tap on the Account icon.
2. On the next screen, tap on Update All option or update individual Apps by tapping on the Update option located next to the Apps.
5. Reset All Settings
Note down the Password for your WiFi Network and follow the steps below to Reset the Settings on your iPhone to Factory default settings.
Go to Settings > General > Transfer or Reset iPhone > Reset > On the pop-up, select Reset Network Settings option.
On the confirmation pop-up, tap on Reset All Settings to confirm.
After the Reset Process is completed, join WiFi Network by entering your WiFi Network Password and check to see if the problem is now fixed.
6. Restore iPhone Using Stable Backup
If you had previously made a backup of iPhone, Restoring iPhone from the Backup should help you fix this problem.
7. Restore iPhone Using Recovery and DFU Mode
If a regular Restore is not working, you can go for Recovery Mode and DFU Mode Restore to fix the problem.
Recovery Mode Restore erases all the Data on your device, reinstalls iOS operating system and provides you with the option to Setup your device as New iPhone or Restore using Backup.
DFU Mode Restore also Erases your device, reinstalls iOS operating, reinstalls device firmware and provides you with the option to Setup your device as New iPhone or Restore Using Backup.
Unless your device has a hardware related issue, any of the above methods should help you fix the problem.
8. Replace the Battery
On older iPhones, the problem of iPhone restarting randomly is being attributed to its deteriorating battery.
If you have tried all the above steps, the last option is to take your iPhone to Apple Care and ask them to take a look at your device.
Apple Care may either advise you to replace the battery or advise you about the hardware issues on your device (if any).