Everything but my background, terminal and right click menu works. However, I'm unable to see the terminal, but it opens. This all started when I recently updated my Ubuntu.
I have attempted to reset unity & the theme back to normal, however this did not resolve my issue.
On my ancient notebook with Intel graphics only, the problem got solved by removing the xserver-xorg-video-intel package as mentioned in another post by user3458301 using the command:
sudo apt-get remove xserver-xorg-video-intel
Had this issue with an old Ubuntu 15.10 installation on a first Generation Intel Core-i notebook.
If anyone gets this problem in the future this is what worked for me
https://wiki.ubuntu.com/Mir/Installing
what you have to do is to install MIR