Try this UDF...place code in a Std Module;
Function File_LastModified(FullFilePath)
Dim FSO, F
'Usage:= Placed in a cell [=File_LastModified(C:ExcelFilesUseful###.xls)]
'Usage:= Placed in a cell [=File_LastModified(A1)]
Set FSO = CreateObject("Scripting.FileSystemObject")
Set F = FSO.GetFile(FullFilePath)
File_LastModified = "Last Modified: " & F.DateLastModified
End Function
HTH
Ivan