If you’re a System Ninja Pro user, you can mount the D:\ drive using the ‘Mount Directory’ tool. In order for this to work, the Firefox profile on D:\ must be located in C:\Users\{name}\AppData\Mozilla\Firefox\Profiles
Free users can use the “Folder/Drive” option in the Scan Inclusions menu. You will need to manually include each directory and select the file extensions you would like removed.