problem in export all tracks as audio files

There is a big problem in logic x which was not there earlier. When i export all the tracks as audio files. It leaves out many tracks randomly .i have tried many ways to crack this without any success. Iam a proffesional music producer, and have to export about 50 60 tracks in each session and i have to bounce each track seperatly which is very time consuming. Please help ASAP. Iam an hardcore apple man and i own all Apple products