Project Description
Enable Outlook OST functionality on a Terminal Server. By default, Outlook 2003/2007 installs are in "Online" mode with Exchange server. Online mode is known to make Outlook sensitive to freezes, hangs etc. An OST file protects you from these issues by creating a local cache of your email data.

This utility was created as a response to a business need my company had. It uses undocumented registry changes that have not been tested by MSFT. Since standard support channels will not help me test this solution, I hope to leverage the knowledge of the codeplex community.

Note: this utility is not needed for Outlook 2010, since an OST is permitted in this configuration.

Important Note from Microsoft

Microsoft Corporation will not support Outlook 2003 that has been modified to operate in cached mode. The only supported configuration for OST use is with terminal servers running Windows 2008 R2 with Outlook 2010. Details are in

- There is potential under this scenario for:
--- Data loss
--- Network saturation of the LAN/WAN links involved as the cached mode clients start downloading Mailbox and Address Book information
--- Disk I/O and disk space concerns on the server where this is done

We instead suggest that you workaround this problem by enabling Outlook Web Access. In addition Outlook 2010 supports cached mode and does not require this registry modification.

Last edited Jul 15, 2011 at 8:38 PM by clamont, version 5