macro loop through all subfolders

See if you can adapt this macro for your purpose:

Sub LoopFolders()
    Dim strFolder As String
    Dim strSubFolder As String
    Dim strFile As String
    Dim colSubFolders As New Collection
    Dim varItem As Variant
    Dim wbk As Workbook
    ' Parent folder including trailing backslash
    strFolder = "C:\Excel\Reports\"
    ' Loop through the subfolders and fill Collection object
    strSubFolder = Dir(strFolder & "*", vbDirectory)
    Do While Not strSubFolder = ""
        Select Case strSubFolder
            Case ".", ".."
                ' Current folder or parent folder - ignore
            Case Else
                ' Add to collection
                colSubFolders.Add Item:=strSubFolder, Key:=strSubFolder
        End Select
        ' On to the next one
        strSubFolder = Dir
    Loop
    ' Loop through the collection
    For Each varItem In colSubFolders
        ' Loop through Excel workbooks in subfolder
        strFile = Dir(strFolder & varItem & "\*.xls*")
        Do While strFile <> ""
            ' Open workbook
            Set wbk = Workbooks.Open(Filename:=strFolder & _
                varItem & "\" & strFile, AddToMRU:=False)
            ' Do something with the workbook
            ' ...
            ' Close it
            wbk.Close SaveChanges:=False
            strFile = Dir
        Loop
    Next varItem
End Sub