Issue that this update fixesAfter you install update KB2817630, the Navigation pane (folder view) is not visible in Outlook.
This issue occurs because a reference is matched to the wrong data structure. This causes the minimize button in the Navigation pane to be rendered at a size that is larger than expected. Therefore, the minimize button prevents the Navigation pane from being displayed.
For more information about this issue, go to the following Office Sustained Engineering and Release TeamBlog: