I'm running Ubuntu 14.04 fully updated on my laptop.
Since the last update every time I lock the screen (when leaving my room for example) - when I get back and input my password, it is not accepted even though it's the correct password, the error I get is:

Password incorrect, please try again

I found that clicking the "Switch Account" fixes the issue but it is very annoying, if you know any way to fix it, it would be nice.
Thanks in advance