weird login password problem

[Federico Bruni <fede@inventati.org>]

Hi all

live-build 4.0.5
debian jessie
lightdm

All of a sudden I cannot login anymore in my installation and I'm 100% 
sure that the password is correct.
This is really weird and I have no idea how to debug it.

Have you ever had a similar experience?

I've tried many builds today so I'm not sure which change triggered the 
problem. It may be because of the preseed.cfg I've added? This is the 
line:

# cat config/includes.installer/preseed.cfg
# skip the root password, user will use sudo
d-i passwd/root-login boolean false

I don't have any other ideas...
Really, I'm sure the password is correct :-)

Thanks in advance
Federico