This error is explained by itself. It denotes the fact that an app has crashed. The application can be restarted, but you can experience the same mistake.
This can be applied to many applications thet can turn annoying.
'Unfortunately Samsung Galaxy stopped' means that refers to a software problem that can usually look like the fact that you need to do a factory reset. You can solve the problem, but do mean that you will lose some data and settings. In any case, you can opt to uninstall and reinstall an application or simply clear the cache.
How to fix crash app in Android?
First you will have to go into the Settings menu and select Application Manager. Click on the tab `all` and choose the application that causes problems. You must do the following: stop Strength, clear the cache and delete data. After all this, you must restart the phone and everything should be ok.