Comment 3 for bug 136688

Okay, lets try the other likely candidate, bug #136433, from this past week that we've identified and fixed.

It is possible automatic updates have already applied this one and the cause is something else, but please check the version of:

$ dpkg-query -l 'powermanagement-interface'

ii powermanagemen 0.3.17 platform neutral powermanagement interface

If you have an older version please check the bug-report above and report back.