I was having the same issue, I have no idea if this was coincidental or part of the issue, I could not log in (Chrome Version 29, Windows 7), until I finally uninstalled, reinstalled, and then actually went through the feature tour. Once that was done, then after a short/sluggish delay, the user id and password prompt appeared. Before that I was just closing that "tour" tab and not letting it (or I guess the JS it loaded) load.