"Audition has reached limit of audio data it can use"

Hey,

I've never come across this problem in the 8 years I've used audtion!

It won't let me edit more than one track at a time, when I try to upload a second track the warning comes to say it has reached it's limit and I need to update cache settings. I thought initially it was because the first track was 2+ hours long but even with shorter tracks (20 - 45 minutes) the same problem keeps happening

I have mutliple times but it keeps giving the same warning, has anyone else come across this?  I'm not sure how to update/clear out old data any other way

thanks