PRB: Out of Office Assistant no longer works after installing ArchiveOne websites

SYMPTOMS
You have installed the ArchiveOne Search & Retrieval website component on an Exchange 2007 or Exchange 2010 Client Access server. You now experience one or more of the following symptoms:

• You receive the following error message when trying to use the Out of Office Assistant in Outlook:
  “Your Out of Office settings cannot be displayed, because the server is currently unavailable. Try again later.”
• Outlook crashes when you try to view a user’s free/busy information.
• When you open the Scheduling Assistant tab in a meeting request in Outlook, you cannot view the free/busy information.

ROOT CAUSE
This is a known Microsoft issue. This problem occurs when the package that contains the .NET Framework 3.5 with SP1 and the .NET Framework 2.0 with SP2 is installed on an Exchange Client Access server.

RESOLUTION
To resolve this issue, please follow the Microsoft Technet article: Outlook 2007 crashes or you cannot access OOF settings after you install a package that contains the .NET Framework 3.5 with SP1 and the .NET Framework 2.0 with SP2 on an Exchange 2007 Client Access server or on an Exchange 2010 Client Access server.