Consider the following scenario:
- You have a mixed Microsoft Exchange Server 2010 and Exchange Server 2003 environment.
- The Exchange Server 2010 server has Update Rollup 3 for Exchange Server 2010 Service Pack 2 (SP2) installed.
- An Exchange Server 2003 user creates a new Microsoft Outlook profile or runs the Test E-mail AutoConfiguration tool in Microsoft Office Outlook 2007 or Microsoft Outlook 2010.
Note To run the Test E-mail AutoConfiguration tool, hold down the Ctrl key, right-click the Outlook icon in the notification area on the right side of the taskbar, and then click Test E-mail AutoConfiguration.
Source: MSExchange Autodiscover
Event ID: 1
Task Category: Web
Level: Error
Description: Unhandled Exception "User setting 'PreferredSite' is not available."
Event ID: 1
Task Category: Web
Level: Error
Description: Unhandled Exception "User setting 'PreferredSite' is not available."