After hours and hours browsing the internet to find a fix for the dreaded "Cannot Stream required archive Data" error with tons of non working pseudo-solutions, I finally thought "mmmh! maybe those guys at emucoach, with their awesome server, know something about it!" and, there it is, finally the solution that works : https://www.emucoach.com/tutorials-...rchive-data-wow-error-134-4-3-4-cataclysm.htm.