Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz 3.40 GHz
RAM 8.00 GB
Windows 7 x64
Environment
Please fix this! It's destroyed all my redstone mechanics and I'm not see my skin!
Video: http://youtu.be/CVZe8_Jw2BA
Thanks in advance and sorry for my bad English (I'm study hard to learn it!)
This issue has been reported already. It has been linked to the original bugreport.
Please search before reporting any bugs, as it's likely that one exists already.
If you're worried that your worlds break, then the snapshots are not for you. These are experimental after all.