f42 default background not working

[François Patte]

Bonjour,

I upgraded to f42 from f40 using the dnf system upgrade, everything 
seems to be alright, except the default background which is missing on 
the logging screen (black) and also when users are logged (white).

I use lightdm and all files in /etc/lightdm and /usr/share/background 
seem to be correct....

What can I do?

Thank you.

F.P.