I had teh same issue, but turns out that the following two packages were not installed:
unity-gtk-module-common unity-gtk3-module
The following fixed it for me:
sudo apt-get install unity-gtk-module-common unity-gtk3-module
On side note why this has happened to me is cause of this bug during the upgrade:
https://bugs.launchpad.net/ubuntu/+source/tex-common/+bug/1241563
Which broke my upgrade progress, I was only able to continue it with sudo apt-get install -f which most likefly failed to install new packages as it didn't know about them
I had teh same issue, but turns out that the following two packages were not installed:
unity-gtk- module- common unity-gtk3-module
The following fixed it for me:
sudo apt-get install unity-gtk- module- common unity-gtk3-module
On side note why this has happened to me is cause of this bug during the upgrade:
https:/ /bugs.launchpad .net/ubuntu/ +source/ tex-common/ +bug/1241563
Which broke my upgrade progress, I was only able to continue it with sudo apt-get install -f which most likefly failed to install new packages as it didn't know about them