If you share your computer with other people and use all the same Windows users there can be annoying voice recent documents that show just the last documents you have open.
In order for this item is permanently empty, without going all the time to delete it manually, just go to the following registry key:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
and enter the DWORD value named "NoRecentDocsHistory" set it with value = 1
The same procedure should also be made to the registry key:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer

So to apply the last changes you must restart the computer.