The bug i have recently found is in Minecraft launcher 1.3.6. The bug will not allow me to access Minecraft 1.7.4/1.7.3.

The launcher is not allowing me to play latest vesion.

I was expecting to play minecraft 1.7.4...:

It showed me the new mojang system pic then
it canceled the game*
1.First, open 1.7.4
2.then press play
3.then it happens