It could be that the files you downloaded are not for MAC. choose .sit or .dmg files to be safest. After a download completes (watch Mac's window), double click and choose "Reveal in Finder", then double-click the download. This is preferable to the other suggestion (drag-and-drop) because you will have a Finder window open of the folder that will be unstuffed, and the results are more obvious. Then work with the new files/folders (or download again if you get a disk error. If MacZip is not responding, you may need to restart your Mac after the install or reload it. Good luck - and send me a private email if difficulties continue; I'm glad to help.