Hi Toby,Please try this workaround (it also works in Windows 10 64-bit)
:I had the same problem (When I drag the folder onto the HTML Article
Packager, nothing happens) on Windows 8 64-bit until I copied all the
files on USB key ( into G:\DPS_2015) to try on the different PC:3 files
from C:\Program Files (x86)\Adobe\ArticlePackagerandHTML Article
Packager shortcut from desktop.Then for HTML Article Packager change
properties "Target" and "Start in"
toG:\DPS_2015\article-packager.batandG:\DPS_201...