I am using logic 9 express on iMac OSX 10.6.8. When I copy a piece of audio vocal from one track into a second track, to replace poorer vocal there, I accomplish this but get a bad clicking sound on playback of that region where I pasted. I have tried bypassing all plug ins and tried first erasing the audio to be replaced. Still have the problem. Any thoughts would be appreciated. I cannot find anything about this on the web.