I did a clean install of Ubuntu Gnome today. I installed cinnamon and switched to it (I left gnome installed). I was customizing the theme, and all settings were taking effect immediately, but I can't change the icon theme. Even if I select a theme and logout and back in nothing changes. Also, if I close the theme window and reopen it, it still has the icon theme that I chose, but it has the icon from the default Adwaita displayed. I ran updates and restarted, and now there is no desktop background and the ctrl-alt-T shortcut for terminal isn't working. I have tried reinstalling cinnamon, and nothing changed. I am running Cinnamon 3.2.7 on Ubuntu Gnome 17.04.
When I select a theme for icon in cinnamon nothing happens. I can change all of the other theme settings. After a reboot the desktop is black and some keyboard shortcuts don't work.