Microsoft Recalls it's September 2013 Office patch - Outlook Folder Pane Disappears

Outlook 2013 Folder Pane Disappears After Installing September 2013 Public Update

The Microsoft Office Sustained Engineering Team
11 Sep 2013 11:48 AM

Shortly after publishing the September Public Update, we received notifications of a potential issue with Outlook 2013 after installing the non-security update KB2817630. Based on those reports we immediately removed the patch from Microsoft Update - within 3 hours of its release. If you haven’t already downloaded or installed the patch, you will not have these problems or be offered the problematic patch.

In contrast to what has been reported, MS13-068 is not the cause nor is it affected by this issue.

This blog post will describe the problem and explain how to fix it. It also reminds users what to do if a Patch Tuesday update causes issues.

We are very careful with Public Updates given their wide and rapid proliferation. We regret any inconvenience caused by this update, and we are hopeful that this information can help you restore productivity in Outlook products.
Understanding the issue

Due to a version incompatibility between outlook.exe and mso.dll, a mismatched reference to a data structure causes the “Minimize” button in the navigation
pane to render incorrectly, typically extremely large to the point that the navigation pane is "invisible" to the user.

The incompatible state is created by installing either the September Public Update OR the August Cumulative update, but not both. Users of MSI-based products that have automatic updates enabled are those that are most likely to have encountered the issue.

Office 2013 Click-to-Run products are not affected.
Office 2013 Versions Affected

Office 2013 Standard
Office 2013 Professional Plus

Said differently, only MSI installations of Office or Outlook 2013 are affected. These are volume-license installations typically found in businesses that
purchase licenses in volume.

Each version of Office installed, such as viewers, standalone client products, Office suites with MSI-based installations, etc., will receive the update. We have
seen reports of some users needing to remove the update 2 or 3 times. This is because the system has product ID’s for multiple installations of MSI-based
Office products.
Office 2013 Versions that are NOT affected:

Office 2013 Home & Student
Office 2013 Home & Business
Office 2013 Professional
Office 365 Home Premium
Office 365 Professional Plus
Office 365 University
Office 365 Small Business Premium
Office 365 ProPlus
Office 365 Enterprise

How to fix affected installations:

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.
How to obtain support:

When you encounter trouble with a Public Update, you can always contact us at Microsoft Support. You can call Microsoft directly at 1-866-234-6020. Alternatively, please contact our community network at Microsoft Community or visit Microsoft Support for access to extensive online self-help resources.