Unity issues suddenly in an Ubuntu 16.04LTS installation

Question

I suddenly had my unity crashed. Dashboard and launcher have suddenly stopped functioning.

I saw the following thread: Unity doesn't load, no Launcher, no Dash appears

However when executing the command

DISPLAY=:0 ccsm &

I am receiving the following error:

"*ImportError: /usr/lib/x86_64-linux-gnu/libharfbuzz.so.0: undefined symbol: FT_Reference_Face*"

I also tried to reinstall unity by running

sudo apt-get install --reinstall ubuntu-desktop

and

sudo apt-get install --reinstall unity

but the same issues appear.

Any ideas on what is the problem?