file://xxx/proxy.pac always resolves to DIRECT by googleupdate.exe about omaha HOT 5 CLOSED

Maybe Omaha does not like file://.

Looks that's the issue. Actually Omaha doesn't use the proxy script URI 
directly but 
passes it to function WinHttpGetProxyForUrl. WinHttpGetProxyForUrl then calls 
WinHttpSendRequest to get the script file. Unfortunately WinHttpSendRequest 
can't 
handle scheme file:// and fails with 12006 (ERROR_WINHTTP_UNRECOGNIZED_SCHEME) 
whiche 
translates to HRESULT 0x80072ee6. Directly specifying c:\proxy.pac doesn't work 
either. 
The fix maybe to use InternetGetProxyInfo() from wininet. End user can also 
move the 
wpad.dat file to a http server to workaround the issue.

I only copied the first user report. More user reports can be found in the 
original 
Chromium bug at http://crbug.com/42615.

In the following thread, someone from Microsoft confirms that WinHttp does not 
support 
local files and that WinINET does. He also suggests a solution at the end of 
the 
thread.

https://groups.google.com/group/microsoft.public.winhttp/browse_thread/thread/43
fc7c8c1
7aa4e62?pli=1

Omaha3 has been released, and adds support for local .PAC files.