Unity 5 64x Build bug ?

hello everyone, i am a user unity 4x but when i migrate my project for unity 5x, i can’t build a project., on half of progress the unity freeze ,
and in the 4x this did not happen
is a unity bug or this will solve if i instal unity 5x 86x(32x) ???
someone can help me ?

thanks in advance

What does your editor log say?