Autoconfiguration was unable to determine your settings!

Hi folks,

One of my customers was saying that some machines were not able to retrieve the Autodiscover settings in Outlook internally with the following error message:


Before doing a deep drive on the server side I asked the guy a couple of simple questions, such as:

  • Do you have success in different computers? The answer was yes.
  • If you log on with a different windows profile on the same machine, does it work? the answer was Yes.

At this point the odds are that is an issue on the client side, just to be safe I went ahead and made sure that all Webservices URLs on the CAS servers on the site where the client was located had the same configuration and after some research I found out that there is a Registry Key that allows to change the Autodiscover behaviour on the client side.

Let’s open the regedit on the affected user and go to HKEY_CURRENT_USERSoftwareMicrosoftOffice<OfficeVersion>OutlookAutoDiscover and on that key you may have the following entries:

  • PreferLocalXML
  • ExcludeHttpRedirect
  • ExcludeHttpsAutodiscoverDomain
  • ExcludeHttpsRootDomain
  • ExcludeScpLookup
  • ExcludeSrvLookup
  • ExcludeSrvRecord

When the value of those keys are set to 1 you disable such feature, in my client I had all of them set to 1 and that was the reason for the issue. You can safely delete those or set them to 0 and then close and open Outlook and voilà Autodiscover is working like a charm again.


Note: The root cause of this issue (and that was on my case) was the Office 365/BPOS installed on the client however different applications/providers can take advantage of this registry key in your environment.