I've logged in every day since we moved to the client - just since the update last night I started getting the 'Your client could not be updated!' pop-up about 15 seconds after the first client window opens. There is nothing I can do from there but click on OK which terminates the whole process.
I play on a desk-top with Windows 10 64 bit system - have never used any facebook or other way to log in other than from my chrome browser.