Allegedly, on or about 24 December 2015, Walter Cazzola sent:
I have let the installer create my user and it has given it uid 1000 and gid 1000. This is the standard behavior and I'm used to change it by manually edit /etc/group and /etc/passwd but this time this behavior has broken my user. I can't enter at the kde login (before in the splash screen it was asking for the password of my user than asking for a password but no user was specified and I got a login erro when I use my passowrd).
Edit those files to change the IDs. chown recursively the /home/username in question Likewise with /var/spool/mail/username in question Delete and /tmp/ files belonging to the username, just in case anything has lingered.
But what have you changed the ID values to? Have you set them lower than 1000? That will probably affect login.
For what it's worth, when I set up a new system, my philosophy is to set up a test user or two, as well as my own username. It may be worth while doing that first, then setting up yourself with a higher ID. Giving you some non-valuable logins to test things with.