I've got the same problem.
i retyped my username, deleted cache, set run in compatibility with windows 8 , run as administrator, unmarked all folders, files subfolders and subfiles for read only
i' ...
Name (InGame): Halderos
Character race/class: Human Warrior
Your Transmog (costume) name: Truth Bearer Shoulderguards + Light-Touched Breastplate + Faith Bearer's Gauntlets + Studded Girdle of Vir ...