[MC-16384] clicked play, minecraft opened for about half a second then crashed.

I expected minecraft to open normally
it opened for about half a second then crashed.
click play when you have selected snapshot 13w21a

Environment

OS: Windows 7 (ver 6.1, arch amd64)
Java: 1.7.0_15 (by Oracle Corporation)
Launcher: 0.8.1 (Dev) (bootstrap 2)

Please attach the crash report, otherwise this ticket is incomplete.

Duplicate of MC-15423.

i posted it because it was launcher 0.8.1 unlike others

MC-16384 = A duplicate of MC-15423