Here are the possible solutions which you can try, in case your Galaxy S6 keeps rebooting by its own:
Wipe Cache Partition is one of the first workarounds used by many to fix other Galaxy S6 issues including overheating, battery draining quickly, blank screen/no display, etc. Performing this method will delete all temporary system files including those that are corrupted and causing problems or errors. The process won't delete personal data though, unlike factory reset. Here's how to wipe cache partition on your Galaxy S6:
- Power off your phone completely.
- Press the Power, Volume Up and Home buttons simultaneously.
- When the phone vibrates, release the Power button but keep pressing the other two buttons until you see the small menu on screen.
- Scroll to Wipe Cache Partition using the Volume down key.
- Highlight the option using the Power button.
- Wait until the entire process is finished (most likely it could take a few seconds).
- When the previous menu shows up, scroll to and select Reboot System Now.
- Use the Power key to run the entry.
- Wait for your device to reboot. It could take a few seconds or longer.
However, if the problem persists after performing wipe cache partition, your next option would be a master reset/factory reset. Although you have to remember that this process will erase everything from your device including your personal information and customized settings. That being said, creating a backup is highly recommended before you begin the process.
If neither of these workarounds works, then here's another solution shared by one of the Galaxy S6 owners who have experienced the same problem. You too can give this method a try on your end if needed.
- Go to your phone Settings.
- Select Display and wallpaper.
- Tap Screen mode.
- You will then see the default option is set to Adaptive display.
- Select any other settings instead of using the default.
- Try to select AMOLED photo.
- Restart your phone and it should be working fine already.