Comment 48 for bug 1228360

I'm also an affected user. Today after the first startup of the machine the indicator dissapear. I applied the solution of Billisaacs after just killing the the unity panel this appears in my terminal.

**@MyComputer:~$ apt-get install indicator-datetime
E: Could not open lock file /var/lib/dpkg/lock - open (13: Permission denied)
E: Unable to lock the administration directory (/var/lib/dpkg/), are you root?
**@MyComputer:~$ killall unity-panel-service
**@MyComputer:~$

And after that, the datetime indicator appears. I have to note that I "killed" the unity panel service before, but the datetime indicator didn't appear, and my "Date time settings" continued grayed. After run the Billisaacs solution everything was fine. So, maybe for some reason, the lock file is not cleared properly after upgrade which (I think) explains why it affects only the user who uses more the machine, which usually is the same user who do the updates.

My two cents and sorry for my English. I'm not a native speaker.