...taking Windows Mail out of the equation,what's the issue exactly? I have Vista, and using Desktop Manager 4.2.*,without an issue. Albeit, I only use it for backups...
The issue lies with not being able to sync contacts / calendars / tasks / memo's with Windows Mail as the contact management software. I understand that WM is the next generation of Outlook Express - however from what I've been able to find on the BB FAQ boards --- they do not have a way to sync WM info to the BB with Vista.