Since this was always a bundled product, I do not believe a pdf of the help file was ever created. There is a windows help file, which is usually the basis of Cakewalk pdfs anyway. You can bring up the help by hitting the F1 key when the DropZone GUI is in focus. If that fails, click on the DropZone text in the upper right-hand side of the DropZone GUI then hit F1. If that fails, the chm file is located in a Documentation directory directly under the directory containing the DropZone dll, the default location in 64bit SONAR is "C:\Program File\Cakewalk]Vstplugins\DropZone\Documentation\DropZone.chm"