Where seeing an issue with a small amount of users - and handful out of 7000 migrated to 2k7 where spell check is not working in OWA. It also appears to only be occuring when users access OWA from within the corporate network. The only common denominator is - when a user clicks on "New" to create a new message in OWA - The zone changes from "Intranet" to "Unknown Zone(Mixed)". Trusted sites/zones are all handled via GPO here. Machines exhibiting the Unknown Zone(Mixed) issue have the same Group Policy applied that systems that work do (verified with GPResult). We were speculating that it may be a setting in IE 7 that isn't handled by policy but could not locate. OS is XP. Wrkstn DNS settings are consistent and a tracert to the OWA infrastrucure is consistent between 2 machines as well.