When uninstalling the Outlook Plugin or document drop you may find that the normal steps taken to remove the necessary files will not work. Microsoft have made some system changes in windows 8 which will require a new method of removing these files.
Open Internet Explorer go to Tools -> Manage Add-ons -> Show: All add-ons:
Right click the document drop or outlook add on and select more information:
Highlight the file and select remove/disable.