In this query, in the
INSERT INTO [MS Access;Database=" + Access + "].[NMS_List_Export] SELECT [IP Address] as [IPAddress],[MAC Address] as [MACAddress],[Last seen on Channel] as [LastseenonChannel] FROM [NMS_List_Export$]"
, use the Replace keyword on the MACAddress.
[IPAddress], Replace([Mac Address],':',' ') as [MACAddress]
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