I have a Fedora 27 64bit workstation.
After the todays update, which has kernel x86_64 4.14.6-300.fc27 plus some other updates (*) the system boots but upon login to user, the background image is shown and nothing else. No desktop, no menu bars (I use Mate), nothing at all. The system is working, I can login from another one via SSH, but it is not working as graphical workstation anymore. I tried using older kernels from the grub menu, but the behavior is the same, so it must be not kernel related.

Hardware: HPZ800, 2X Xeon5670 +24GB RAM, 256GB SSD, Nvidia Quadro 600 VGA. Using nvidia driver, nouveau disabled.

(*) except the kernel update, other updates, probably related are:
gnome-software x86_64 3.26.5-1.fc27
sane-backends x86_64 1.0.27-9.fc27
sane-backends-drivers-cameras x86_64 1.0.27-9.fc27
sane-backends-drivers-scanners x86_64 1.0.27-9.fc27
sane-backends-libs x86_64 1.0.27-9.fc27
webkitgtk4 x86_64 2.18.5-1.fc27
webkitgtk4-jsc x86_64 2.18.5-1.fc27
webkitgtk4-plugin-process-gtk2 x86_64 2.18.5-1.fc27