Hi Mark,
Try this code. I have stared using something like it since I switched to Win2K and VFP 7 because it requires WMI (and the VFP 7 IMoniker support enhancement to GetObject is required).

omgr = GETOBJECT("WinMgmts:")
oadaptercol = omgr.InstancesOf("Win32_NetworkAdapterConfiguration")
IF oadaptercol.Count > 0 then
   * go through each adapter configured on the system
   FOR each oadapter in oadaptercol
      if type("alen(oadapter.Properties_('IPAddress').Value)") = "N" then
         * check was done to handle WAN adpaters that are configured on the
         * system however they don't have IP addresses so disregard them
         ? oadapter.Properties_('MACAddress').Value
            for each cIP in oadapter.Properties_('IPAddress').Value
               ? cIP
            endfor
      endif
   ENDFOR
ENDIF
return

HTH.

>I have run this code multiple times on a Dell 8100 Inspiron, Win2k machine, and I get a totally different return value every time. I have found absolutely nothing that can consistently return the correct MAC address of the primary adapter.
>
>P.S. I do realize this thread is 7 months old. I am still searching for a way to do this and finally found this and other thread with the search engine.
>
>>Rick,
>>Because a GUID uses the MAC address of the primary network adapter to make sure its unique, you can create a GUID and parse it for the MAC address.

>>clear
>>local lcguid
>>lcguid = GetGUID()
>>return substr(lcguid,26,2)+'-'+substr(lcguid,28,2)+'-'+substr(lcguid,30,2);
>>	+'-'+substr(lcguid,32,2)+'-'+substr(lcguid,34,2)+'-'+substr(lcguid,36,2)
>>
>>function GetGUID
>>local lcStrucGUID, lcGUID, lnsize
>>declare integer CoCreateGuid in Ole32.dll string @lcGUIDStruc
>>declare integer StringFromGUID2 in Ole32.dll string lcGUIDStruc, string @lcGUID, long lnSize
>>
>>lcStrucGUID=space(16)
>>lcGUID=space(80)
>>lnSize=40
>>
>>if CoCreateGuid(@lcStrucGUID) # 0 then
>>   return ""
>>endif
>>if StringFromGUID2(lcStrucGUID,@lcGuid,lnSize) = 0 then
>>  return ""
>>endif
>>return strconv(left(lcGUID,76),6)

>>GetGUID code was posted by John Koziol (who I believe got it from Rick Strahl) here last year.
>>
>>HTH.