The issue appears at this time to be related to how Windows 2008 clusters handle file share / file server resources.
Install KB 955733 - Incorrect status codes that are returned in failover clusters may cause operations to fail on a Windows Server 2008-based computer. This ensures that the cluster returns the correct status codes where necessary.
In case you have unsolved issues with Outlook, check the list of issues fixed here to see if they might finally be resolved now.
I’m hearing good things about Outlook 2007 SP2 in regards to performance, and this seems to be a step in the right direction (even though it isn’t SP2 yet).
It brings your Outlook build to:
12.0.6335.5000 SP1 MSO (12.0.6333.5000)
Outlook update from October was:
12.0.6331.5000 SP1 MSO (12.0.6320.5000)
Super fun fact for the curious:
The MSO build/revision number is related to the Office shared DLL called MSO.DLL. It is used by practically all the Office suite. Most of the fixes in this release seem to be related to the shared DLL.
Noteworthy fixes (to me):
When the sender of an e-mail message has Send As permissions to another mailbox, the From field of the printed e-mail message incorrectly contains "on behalf of" text.
The same profile is listed two times in the Choose Profile dialog box of Outlook 2007 when you create a new profile that contains some extended characters in the name. This issue occurs if the Outlook Mobile Service Add-in is enabled.
Outlook 2007 may crash if an application on the Microsoft Exchange server responds to port 80 requests for availability information from Outlook.