Hybrid Free/Busy lookups might fail if Outlook Anywhere is disabled

Recently, I bumped into Jaap Wesselius’ article about an issue he encountered about Hybrid Free/Busy lookups failing. As this relates to Hybrid Exchange, I was – of course – intrigued and remembered that I (once) encountered a similar scenario, but could not remember how I resolved the problem back then.

After some digging, I came across the following KB article which describes the behavior of Free/Busy requests and why they might fail of Outlook Anywhere is disabled (blocked) on the user-level: http://support2.microsoft.com/kb/2734791/en-us?sd=rss&spid=13159

To make a long story short, if Outlook Anywhere is disabled at the user level, Autodiscover does not return the External EWS URL which is required to make the Free/Busy call.

The solution is as simple as the problem itself: re-enable Outlook Anywhere for the user and you would be fine. Of course, this might – depending on your environment – be a little challenging. This being said, however, I do suggest that you configure and (if possible) use Outlook Anywhere as it will make your life easier down the road (e.g. for migrations to Exchange 2013).

Exchange 2013 Hybrid Exchange Office 365

You get and Autodiscover Error : Unhandled Exception "User setting ‘PreferredSite’ is not available. " after installing Exchange 2010 SP2 Update-Rollup 3

After installing Exchange 2010 SP2 Update-Rollup 3, you might see the following error pop-up in the event logs: Unhandled Exception “User setting ‘PreferredSite’ is not available. “


Although at first not much information was available, Greg Taylor already said on the 13th of June that the error is known and they were looking into it.

Apparently, Scott Schnoll also mentioned this in his presentation @ TechEd, stating the following:

(I haven’t had the chance to view the recording, but thanks to my colleague Dave for pointing this out!)

It’s good to see that the errors (although presenting them as critical), do no harm. Unfortunately, the more mailboxes you have, the more errors you’ll have in your event log. From what I can see, there might even be an error every few seconds; therefore possibly flooding your event log.

Microsoft will make an Interim Update available. However; at time of writing no fix was available yet.