For those of you who don't need the Log Off User option, these are the steps to remove it.
Flare up registry editor.
Scroll to HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
Right-click on the right pane and select New, DWORD Value. Name it NoLogOff.
Double-click and enter 1 as value. To restore the Log Off User option, reverse the steps by changing 1 to 0 or delete DWORD value.