Safe Mode on Android is quite useful to diagnose issues with third-party apps. If your phone crashes occasionally, if it slows down, or if it act unstable, many a time, it can be due to third party apps installed on your phone. If your phone works without any issue when in safe mode, it means the problem is due to a third party app you have installed.
In Safe Mode, Android will disable all third-part apps that you have installed on your phone. Instead, the operating system will be as it is fresh from a factory restart, with only the native apps present.
To boot your android phone into Safe Mode, unlock your phone, long press the Power button and when the power menu is displayed, long press the “Power Off” option. A Reboot to safe mode” dialogue will be appearing asking you to confirm the action. Just tap Restart.
Now, to diagnose any issue, try to recreate the behavior causing problems. Also, in Safe Mode, you can uninstall and reconfigure problem-causing apps. For instance, when you are running a newly installed app, if it forces closes and reboot your device, just remove it from your device. To exit safe mode, you just restart your device as you normally would.