Fade Out Works, But Fade In Doesn't

I have Sonar 7 and have used the Envelope Function on the Master Fader before with no no problem for fade outs or fade ins.  For my current project, before I export my mix, I can hear the fade in and fade out no problem.  When I export my mixes and listen back to them, all my mixes are not fading in.  The fade out works fine.  I have made sure the "Read" button is on on the master section, and all the boxes except "64 bit engine" are checked on the export window  I am using ASIO drivers.  What am I doing wrong?  Thanks!