For those random people having random issues with logins lately..it may not be your Linux distro. Apparently a nasty bug has creeped into ext4, which is causing all kinds of mayhem. Make sure when installing a new distro, you mount your /home directory as something besides ext4 in order to keep your data safe. See this link, scroll down to the Section entitled Tips and Tricks (by Robert Storey) to see more of what’s going on, in case you are affected. Not a lot of people are at this point, supposedly just randomly. The chief maintainer of ext4 is working on a solution now.