After my latest
sudo apt-get upgrade the launcher and the start bar on the left-hand side did no longer appear. Also, the Terminal did not load up when pressing CTRL + ALT + t.
Ubuntu 14.04, 64 bit, desktop/notebook, Unity - with all current updates installed.
Update: The reference from David Foerster here below in the comments contains several fixing approaches. However, I would suggest trying the answer here below first. It seems to be one of the easiest and most reliable, and you don't have to play round with graphic card drivers, the 'Ubuntu Unity Plugin' or setting up temporary display variables.