I've experienced this problem with several Outlook 2011 installs and haven't been able to find a solution short of a complete office uninstall and reinstall. Even then restoring use of the navigation pane doesn't happen.

Here's what's happening: When the navigation pane is active per View/Navigation Pane, the Outlook mail window locks and renders everything unclickable/unusable. No mail displays and the window appears locked/frozen. Menu items can be accessed. With the navigation pane unchecked in View/Navigation Pane, the mail window functions--of course without the navigation pane. This has happened with new installs after font import and on existing systems without any overt font install (or other install). 

If I switch users, the navigation pane works, so it appears to be something related to the user account. In the case of the most recent occurrence, both tested user accounts have admin privileges. 

I've run into this several times during system setup and now on an existing system. Anyone else experience this? And is there an easy solution?

Thanks.