Comment 80 for bug 39315

I rebooted in to the old kernel to check if that was the issue or not. It made no difference.

I then rebooted and removed the new three packages that I had installed (in addition to the updates). They were openswan, ipsec-tools and secvpn. I rebooted and tested again -- it still didn't fix the problem.

I then did:
dpkg -r openswan; dpkg -r ipsec-tools; dpkh -r secvpn
and
dpkg --purge openswan; dpkg --purge ipsec-tools; dpkh --purge secvpn
... and rebooted.

This appears to have fixed the problem. So, to recap, for me, the problem appeared to be caused by one of those three packages, and was only fixed after I completely purged them from my machine (apt-get remove <<package>> didn't appear to completely remove them - the --purge seemed to do the trick).

Hope this helps some of you track down your problems. Possibly try:

dpkg --purge plptools ?