Ok - here is what I found:
Just deleting picture files works ok for some, but did not work for me. I'm just a noobie, yet I suspected that is only half of the solution. From research - it is clearly important to clean this folder periodically - no matter what.
If your Audio Clips continue labeled "Busy", go to EDIT | SELECT | ALL, type ALT+ENTER, go to the Audio Files tab and click "Recompute Picture(s)". Note::: You must have your interface running (I use Presonnus Firestudio) or you will continue to get busy errors.
Not sure if it helps your issue but solved mine. Good luck.
King