Hi
before the procedure where you contextmenu is fired (i suppose on rightclick somewhere) can prevent the menu to appear by this code

	    Wait Window Reccount(Thisform.grid1.RecordSource)  Nowait  &&for visual only
	    If Reccount(Thisform.grid1.RecordSource)=0
	      Messagebox("Grid empty..... rightclick blocked!",0+32+4096,1200)  &&for visual only
	      Return .F.
	    Endi
*...follow your contextuel menu

if the recordsource have no record the menu is not fired.