How to disable X server autostart in Debian Jessie

The disable didn't work because the Debian /etc/X11/default-display-manager logic is winding up overriding it.

In order to make text boot the default under systemd (regardless of which distro, really):

systemctl set-default multi-user.target

To change back to booting to the GUI,

systemctl set-default graphical.target

To restore it to how it used to work: Install smbclient:

apt install smbclient

Then edit /etc/samba/smb.conf and add a line 
under the line:
workgroup = WORKGROUP 
##########################
client max protocol = NT1
##########################
Save the file and reboot ... yes ... reboot.


win10

in smb.conf:

###
server min protocol = SMB2_10
client min protocol = SMB2
client max protocol = SMB3