I still have black screen problem even after fresh install from the latest 17.0.1 iso image.
I updated yesterday, manjaro-keyring and manjaro-system, pacman-mirrors were regenerated, then about 700 MB of updates including KDE/Plasma was installed. No errors during update, but after reboot only black screen, no sddm, no gui. I switched to tty2, tried pacman -Syyu or yaourt -Syyu but there was nothing to update. I tried some advices from this forum, reinstalling mhwd, mesa, lib32-mesa, nothing worked.
I installed manjaro from the latest 17.0.1 kde iso image (fresh install, formated / partition), it worked. Then I installed some additional packages, tweaked some settings and after reboot that black screen again. When I switch to tty2, log in and run htop I see sddm and xorg running, but there is no video, only black screen. I tried replace sddm with slim, it worked somehow, there was login screen visible, I was able to enter login and password bud then it failed to log me in and start KDE/Plasma. Screen turned black and then slim restarted. I also looked into journalctl and there was something about opengl but I really don't know what's the problem.
I have a dual boot with kubuntu 16.10 and it's working fine. I don't have enough free time to investigate this issue more. Have someone experienced this problem too? I suspect the cause of this can be in graphics drivers, mesa, libgl or something related to it. I have some old nvidia card (GT210/218) and binary drivers from the 340xx branch. But when I tried to remove them and switch to noveau the black screen remained. I'm out of ideas what should I try next.