Maybe run this and see if it works

Public Sub SaveAttachments(Item As Outlook.MailItem)
If Item.Attachments.Count > 0 Then
    Dim objAttachments As Outlook.Attachments
    Dim lngCount As Long
    Dim strFile As String
    Dim sFileType As String
    Dim i As Long
    Set objAttachments = Item.Attachments
    lngCount = objAttachments.Count
    For i = lngCount To 1 Step -1
        ' Get the file name.
        strFile = objAttachments.Item(i).FileName
        ' Get the path to your My Documents folder
        strfolderpath = CreateObject("WScript.Shell").SpecialFolders(16)
        strfolderpath = strfolderpath & "\Attachments"
        ' Combine with the path to the folder.
        strFile = strfolderpath & strFile
        ' Save the attachment as a file.
        objAttachments.Item(i).SaveAsFile strFile
    Next i
End If
End Sub


if this works then try to modify to save your .xlsm file attachment