The first thing I would try is a repair, which loads automatically if you try to do a delete.  Next thing is go to tahe program mode and do a reset of soundpools.  These are 2 separate steps independent of one another, so do one and seeif it fixes the praoblem first...if not do tahe other.  I've had Magix since #15 and hav saved all my soundpools    in a sepaarate folder.....sometimes for some reason, they get messed up and I'll admit sometimes its me....but I just go back to my folder and download what is "corrupt"..."missing"..."broke".  One time Magix had a sound that one of the pitches had a different file extension.....it was like .MMN and not .MMM and guess what, it wouldn't load.  Magaix support was no help....but I found it, renamed the file and it worked great.