See if this Re: Microsoft.XMLHTTP takes from the cache Thread #570570 Message #570643 can be of help (check the whole thread).

>I’m using XMLHTTP control to send and receive data from a web server. As long as the URL’s are unique we are ok but when a URL is repeated it uses the cache info which returns old cached data. How can I clear cache or set a property not to use cache? Example this code will only work once until VFP is restarted.
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>loHTTP = CREATEOBJECT("Microsoft.XMLHTTP")
>loHTTP.open("GET","http://10.0.0.231/state.xml?relayState=1",.F.)
>loHTTP.send()
>?loHTTP.responseText()
>loHTTP = .null.
>
>=WaitFor(2)
>
>*loHTTP = CREATEOBJECT("MSXML2.XMLHTTP")
>loHTTP = CREATEOBJECT("Microsoft.XMLHTTP")
>loHTTP.open("GET","http://10.0.0.231/state.xml?relayState=0",.F.)
>loHTTP.send()
>?loHTTP.responseText()
>loHTTP = .null.
>