I have a customer running SBS 2003 (Exchange 2003) and Windows 7 clients running Outlook 2010. I have found by playing that the Windows 7 Search will not find e-mails unless the Outlook clients run in cached Exchange mode.
I guess that makes sense. If they are not running cached mode there is no file on the workstation (ost) for Windows Search to search. Cached Exchange mode has been known to cause a lot of problems.
Is there a way to run the Outlook clients in non cached Exchange mode and have the Windows 7 Search still search find e-mails?