The solution for me was to go to repair the Office installation from Control Panel/Programs and Features/. First make sure that you only have one install of Microsoft Office. (Uninstalling and re-installing Office does not affect your data.) Remove all unnecessary installs. Highlight the valid install and select Change, from the pop-up select Online Repair and let it run to completion. This fixed the duplicate entries for me. I had a couple of machines where this didn't work and so I used this tool from Microsoft to completely uninstall and reinstall Office 365. On occasion, for really stubborn issues I've used this other tool from Microsoft to help fix them.
If all else fails you can always right click the offending entries and select uninstall.
