I've solved adding this lines in the [Greeter] section of /etc/gdm/custom.conf
[Greeter] #stuff
Include=myusername Exclude=long_list_of_standard_excluded_users IncludeAll=true
#stuff
I've solved adding this lines in the [Greeter] section of /etc/gdm/ custom. conf
[Greeter]
#stuff
Include=myusername long_list_ of_standard_ excluded_ users
Exclude=
IncludeAll=true
#stuff