Endpoint Security and Control clients that connect to a proxy server using WDigest authentication are not downloading updates from Sophos

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  • Updated: 09 Jan 2012


You have set up one or more endpoint computers to download their updates directly from Sophos. However, they are not updating. When you look in the alc.log file, you see:

ERROR:   Download of SAVXP failed from server Sophos

To confirm that this is the issue, look for a file similar to 'ALUpdate20101222T172622.7525000.log' in one of the following locations on the endpoint:

Windows Vista and above: ProgramData\Sophos\AutoUpdate\Logs
Windows XP and lower: Program Files\Sophos\AutoUpdate\Logs

In this log file, you will see one of the following errors:

Can't connect to the service (proxy is not routing traffic)

SDDSUpdateLocation caught exception from BeginSync: Couldn't authenticate user for resource with gateway or proxy server

Known to apply to the following Sophos product(s) and version(s)

Sophos Endpoint Security and Control 9.7
Sophos Endpoint Security and Control 9.5
Sophos Endpoint Security and Control 10.0
Sophos Endpoint Security and Control


Sophos does not support WDigest proxy authentication for updating.

What to do


  • If you are able to, you should set an exception in your proxy to disable authentication for the specific update locations.
  • Change the type of authentication used on the proxy server.
More information about WDigest Authentication is available from http://technet.microsoft.com/en-us/library/cc995189.aspx.

If you need more information or guidance, then please contact technical support.

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