If you (like me) like to live in the fast lane and chose to allow "pre-released updates" in your update preferences, you might find you lost all network connectivity after shutdown/restarting. The culprit is a libnl update (3 packages) that totally borks networking and network manager. You'll have to reinstall the older libnl packages, but you can't because you have no network. Workarounds are to download them on another computer and transfer them via flashdrive, or try a live CD and save them to the drive for re-installation.