Hello Sergio,
The Last saved by/Last author seems to be the User Name(under Tools, Options) of the user who last saved the file.
This Office User Name can be changed. So, you could store the User Name in variable, change the User Name, save the file, set the User Name back to the name that you stored in the variable and close the file. Not an elegant solution ...
Sub test()
Dim oldlastauthor As String
Dim oldauthor As String
Dim newauthor As String
oldlastauthor = ActiveWorkbook.BuiltinDocumentProperties("Last author"

MsgBox oldlastauthor
oldauthor = Application.UserName
MsgBox oldauthor
newauthor = "New Name"
Application.UserName = newauthor
ActiveWorkbook.Save
MsgBox ActiveWorkbook.BuiltinDocumentProperties("Last author"
Application.UserName = oldauthor
ActiveWorkbook.Close
End Sub
It seems that besides this "superficial" and easily accessible information, Excel also stores stuff like last saved by in a different way ...
Ilse