Comment 4 for bug 1389888

Thank you for your fast feedback.

I was not able to execute
 dconf reset -f /org/compiz/
at tty7 because i was not able to open a shell and on tty1 i got the error "cannot autolaunch d-bus without x11 display".

So I did the work myself as good as i could on tty1.
 sudo rm -rf ~/.config/dconf/user
 sudo rm -rf ~/.cache/compizconfig-1
 sudo apt-get install --reinstall compiz-core compiz

After a reboot the unity desktop was working again.
Thank you guys.

I don't know if there is be a better and cleaner solution.

Your unity_support_test returns now

OpenGL vendor string: NVIDIA Corporation
OpenGL renderer string: GeForce GTX 970/PCIe/SSE2
OpenGL version string: 4.4.0 NVIDIA 343.22

Not software rendered: yes
Not blacklisted: yes
GLX fbconfig: yes
GLX texture from pixmap: yes
GL npot or rect textures: yes
GL vertex program: yes
GL fragment program: yes
GL vertex buffer object: yes
GL framebuffer object: yes
GL version is 1.4+: yes

Unity 3D supported: yes