There's lots of error messages - which one?
I don't understand what a T: is
What is your whole macro?
These work for me
Option Explicit
'this adds the creation date for THIS workbook to the left footer on the active sheet in THIS workbook
Sub InsertCreationDate_2()
ActiveSheet.PageSetup.LeftFooter = "&""Arial,Bold""&12 " & Format(ThisWorkbook.BuiltinDocumentProperties("Creation Date"), "yyyy-mm-dd hh:mm")
End Sub
'this adds the creation date for a SAVED workbook to the left footer on the active sheet in THIS workbook
Sub InsertCreationDate()
Dim D As Date
D = CreateObject("Scripting.FileSystemObject").GetFile("C:\Users\Daddy\Projects\Chemistry\ChemHelper_20.xlsm").DateCreated
'the Date, etc. can get formatted: font bold point, etc
ActiveSheet.PageSetup.LeftFooter = "&""Arial,Bold""&12 " & Format(D, "yyyy-mm-dd hh:mm")
End Sub