Programs keep getting pinned to my taskbar

Go to

%LOCALAPPDATA%\Microsoft\Windows\Shell\

Edit LayoutModification.xml (remove the inner taskbar items)

    <CustomTaskbarLayoutCollection PinListPlacement="Replace">
      <defaultlayout:TaskbarLayout>
        <taskbar:TaskbarPinList>
          <taskbar:DesktopApp DesktopApplicationLinkPath="%APPDATA%\Microsoft\Windows\Start Menu\Programs\System Tools\File Explorer.lnk" />
	  <taskbar:DesktopApp DesktopApplicationLinkPath="%ALLUSERSPROFILE%\Microsoft\Windows\Start Menu\Programs\Outlook.lnk" />
        </taskbar:TaskbarPinList>
      </defaultlayout:TaskbarLayout>
    </CustomTaskbarLayoutCollection>