The visible property of the drawings may have been set to false. Try the following:
1. from the worksheet with miissing drawings
2. launch VBA editor using the "Tools:Macro:Visual Basic Editor" menu item.
3. Open immediate window by selecting the "View: Immediate Window" menu item
4 in the immediate window pane type the following.
Code:
?activesheet.shapes.count
and press return
this will return the the number of drawing objects in the active worksheet
If its zero the worksheet is fubar. if not create and run the follwoing macro
Code:
Sub ShowMeTheDrawings()
Dim shp As Shape
For Each shp In ActiveSheet.Shapes
shp.Visible = True
Next
End Sub