I've disabled all other PowerPoint add-ons, and the office tab worked once when I had three .pptx tabs in one view but then crashed. now Powerpoint will not allow me to make the office tab add-on active. it makes it inactive; regardless, if I change the status to active, it throws it back to inactive. I've uninstalled and reinstalled it, and the same happens. open a .pptx file, it says powerpoint has issues with the office tab add-in, and disables it for .pptx.