How To Fix Galaxy S8 That Shuts Down

Sometimes your Galaxy S8 or Galaxy S8 Plus will shutdown unexpectedly. Well explain to you how to fix this problem. This can happen several times without warning. Some times when the Galaxy S8 shutdown itself, you can use some of the following solutions to help fix the problem. Your best option is to get your Galaxy S8 or Galaxy S8 Plus repaired by a professional technician.
If the problem persists even on a new Samsung Galaxy S8 or Galaxy S8 Plus, you should check and see if your smartphone is till covered under warranty. 
Having the Galaxy S8 and under warranty can save serious money when you are having issues with your smartphone. You should get the Galaxy S8 checked out by Samsung Support if you have a Galaxy S8 or Galaxy S8 Plus that keeps rebooting, shutting off or freezing.
Most of the time these issues are due to a defective battery or a new app that is causing your smartphone to crash. Bad firmware can also cause crashes. Here are some way to fix your Samsung Galaxy S8 from unexpectedly turning off.
 
Android operating system causing your Galaxy S8 to shut off
A new firmware update can cause your Galaxy S8 or Galaxy S8 Plus to shut down or reboot itself. If this happens you should perform a factory rest. Here is a guide on how to factory reset the Galaxy S8.
Please back up and save all your data before performing a factory reset because when performing a factory reset, it deletes all your data and restores it to its original settings.
 
New Application causing sudden reboots.
Safe Mode will allow you to securely uninstall applications and remove bugs. You can also use Safe Mode if any old apps no longer work or if the Galaxy S8 or Galaxy S8 Plus restarts unexpectedly.
Here is a guide on how to use the Samsung Galaxy S8 in safe mode. There is a more detailed guide on who to turn “On” and “Off” Safe Mode on the Galaxy S8 and Galaxy S8 Plus, here.
Turn off your Samsung Galaxy S8 completely. Keep the power on/off button pressed to reboot your smartphone. Once the screen is activated and displays the Samsung start logo, immediately hold the volume quieter button. Keep it pressed until the sim-pin is queried. At the bottom left you should now find a field with “Safe Mode“.