superbuyro,
yes, this mistake will cost you a reinstallation. And you are not the only one these days... I think you should save your data and reinstall: this is the most painless procedure i think. If anyone has a better and quite as fast solution let us know.
So, to everyone: BackBox 3.13 is based on Ubuntu 12.04. Don't upgrade to the new Ubuntu release via Update Manager when it asks. Just upgrade packages, better by hand via apt-get, and better disabling those stupid Update Manager notifications at startup.
Good luck!
Bye.