Sun times the experience with the transition from Android 4.4 to Android Lollipop Kit Kat 5.0.1 with a Samsung Galaxy S4.
It looked good at first, but then settled move any apps on the screen, or add new widgets. Each time the error "TouchWiz Start stopped", ie the Laucher from Samsung.
All the tricks from the Internet did not help, such as:
1.) The app S-Planner disable
2.) Switch to simple mode of TouchWiz,
3.) TouchWiz start in application Manager he stop and delete data,
4.) Developer disable options.
The only thing that really helped was a hardware reset, ie reset to factory setting. This means that all arrangements and loaded apps will be deleted.
So before important to back up everything in the Google account and take screenshots of your app arrangements, so you afterwards know what everything was as furnished.
After the fresh start you can see then that all symbols "clean" look and some apps when backing up non-restoring s because they are not compatible with the version. Example: AppMonster