On an HFS+ volume, some Mac software creates "hard links" instead of normal files. Hard links have no content; they are indirect references to regular files. In this way, they are somewhat similar to Windows Explorer shortcuts or Mac OS Finder aliases.
Although the Mac OS Finder shows these hard links as normal files, MacDrive does not support hard links. MacDrive will show hard links as files of size "0KB" (zero bytes).
A hard link can be recognized in MacDrive by right-clicking the file, clicking Properties, and clicking the MacDrive tab. If a file is a hard link, its type will be "hlnk" and its creator will be "hfs+".
While rare, user-created QuickTime videos are the most commonly seen hard links.
Currently, the only workaround is to make a create a copy of the hard-linked file in Mac OS. This will create a "normal" copy of the file, which is accessible by all versions of MacDrive.