This is an upgrade issue we want to share with you.
When you run the Windows 7 Upgrade Advisor tool on a system that must use a proxy in order to access the internet you receive the error:
"Windows 7 Upgrade Advisor was unable to reach the Microsoft server for compatibility information. Check your internet connection and try again later.”
In the error log (%temp%WuaDiagnostics.log) you can see the update advisor tries to access:
http://aeos.microsoft.com/compatibilityexchange/compatibilityexchange.svc and then receives the error like following:
[7/23/2010 12:04:41 PM] Exception: The request failed with HTTP status 407: Proxy Authentication Required
Currently, the Windows 7 Upgrade Advisor does not support proxy authentication.
We should make some changes on the proxy, creating an anonymous access rule specific to the destinations FQDN's used by the Windows 7 Upgrade Advisor, for example, you may create the following rules:
Protocols: HTTP, HTTPS
To: Domain Name Set
Update: a KB was published for it: http://support.microsoft.com/kb/2448270