Reviving this old thread to post a solution I was able to come up with, after struggling with this problem for a long time. Navigate to your GW2 installation folder and create a new empty text file. Name it KBDUS.dll. Make sure the extension actually changed.Next, right click the file and go to Properties > Security > Advanced > Disable Inheritance, and pick Remove all inherited permissions from this object. The goal here is removing every user's permissions from accessing the file at all. After all that's done, start GW2 again. It shouldn't add the US keyboard layout anymore. If you ever need to delete that KBDUS.dll file, you will have to restore the file's permission inheritance first (follow the same steps, the button to disable inheritance will have changed to enable inheritance).