Why when I download a file is it only several kilobytes in size?

This can happen when files are linked to using scripts rather than direct web addresses. Files hosted on some virtual drive file storage servers are well notorious for this problem. Usually the files have not been deleted, the download is just being mismanaged because the real location of the file is not evident in its URL.

To sidestep this quandary you can temporarily disable any download manager browser integration features by holding down the shift button when clicking on the target file(s). Doing so will either whisk you away to another page containing a direct link to the individual file, which can then be dragged into your download manager, or redirect you to the file itself without revealing its true location, which will automatically begin downloading independent of your download manager.