Mapping on Cross not working

Please can somebody help me. I am using Cross 3.2.1 and when I am playing 2 tracks but the Cross fade is to the far left it continues to play music coming from the right channel. I have already tried reinstalling the software, restarting my machine etc. but it continues to not work properly.
I am playing on a mac.
Please can somebody help me or pint me in the right direction on this forum.
I am playing on a mac.
Please can somebody help me or pint me in the right direction on this forum.