or copy C:\Program Files\Autodesk\Maya8.5\scripts\startup\FileMenu.mel
and then edit this area with a enable comamnd
CODE
menuItem -label (uiRes("m_FileMenu.kSave"))
-annotation (uiRes("m_FileMenu.kSaveAnnot"))
-en 0
-command ("SaveScene") saveItem;
menuItem -optionBox true
-annotation (uiRes("m_FileMenu.kSaveOptionsAnnot"))
-command ("SaveSceneOptions")
saveOptions;
then save as this FileMenu.mel to
C:\Documents and Settings\%username%\My Documents\maya\8.5\scripts
it will be more usefull if u doing your project in sever based