Ubuntu 16.04 software center not working [duplicate]
Type the following in the terminal in order to update gnome-software, which should fix the problem:
sudo apt-get update && sudo apt-get install --only-upgrade gnome-software
You can also update using the graphical update manager, which will do the same thing.
(The version of gnome-software shipped with Ubuntu had a bug which meant that it sometimes wouldn't start, which was fixed in a update)
I had the same issue. I looked on the dashboard and had two Ubuntu Software programs installed. Deleted the old one (Ubuntu Software Center). That fixed my problem.