同事电脑MS Office由2010升级到2013出现这个问题，Outlook的侧边文件夹，如Inbox及下的文件夹点开显示按钮显示一下及消失，网上查询是WIndows update导致，具体处理方法如下：
Two updates can get a user into this state. Installing the September Public Update delivers an updated version of mso.dll without updating outlook.exe, resulting in the incorrect user interface.
If you have Automatic Updates enabled, visit the Add Remove Programs feature of your Windows Installation, and uninstall KB2817630. Close Outlook and restart.
If you have installed the August Cumulative update (which you must do manually), removing KB2817347 will correct the issue. From the Add Remove Programs feature, select KB2817347 from the list and select “Uninstall.” Close Outlook and restart.
If you have BOTH Updates installed, the problem is not evident. The issue only manifests when one of the updates has been installed. If you have updated to the September Public Update and you want to roll forward, install the August Cumulative update, KB2817347.
We are also working on re-publishing the September Public Update with the correct versions of both mso.dll and outlook.exe to ensure users with automatic updates enabled will receive the correct fix. We will update this blog with further information as our schedule develops.
但是我无法找到这两个更新：KB2817630和KB2817347，只有相近的更新包，如KB2817629，于是我将其删除，重启电脑，开outlook发现问题也可解决。
原文地址：http://helpdesk.blog.51cto.com/219783/1744643
