Problem in mcpe 0.6.1

What I expected to happen was...:
Describe what you thought should happen here

What actually happened was...:
The game crashed on me and did not save.
Steps to Reproduce:
1. The Game Crashes on me sometimes when i build or play multiplayer on survival and creative
2. The Game sometimes does not save like on my creative world i opened the door and closed the door and exit and go back and the door is opened.
3. Also can you do a new bug fix update.