December 5, 2017, update for Outlook 2016 (KB4011570)

Applies to: Outlook 2016

This article describes update 4011570 for Microsoft Outlook 2016 that was released on December 5, 2017. This update has a prerequisite.

Be aware that the update on the Microsoft Download Center applies to the Microsoft Installer (.msi)-based edition of Office 2016. It doesn't apply to the Office 2016 Click-to-Run editions, such as Microsoft Office 365 Home. (How to determine?)

Improvements and fixes

This update fixes the following issues:

  • Outlook 2016 crashes when you scroll in the Calendar view if the mouse wheel is disabled. 
  • You see incomplete time zone information on Outlook calendar items that are imported from CSV or SharePoint files.
  • The Track Changes feature is enabled unexpectedly on meeting requests that are sent from public folders.
  • When you start Outlook 2016, Outlook 2016 may freeze because of a hidden credential prompt.
  • An issue that causes Outlook to crash when you read an email in the preview pane.
  • The number of unread messages is displayed incorrectly and not updated expectedly in Outlook 2016.
  • Some appointments are saved incorrectly when you save an Outlook calendar as an iCalendar (.ics) file.
  • Third-party MAPI providers may be blocked despite they are in the Outlook profile.

This update also contains the following fixes and improvements:

  • When you use the Japanese version of Outlook 2016 together with an IMAP server, invalid characters, such as a zero-width space, follow the name of the Drafts folder in the IMAP server.
  • Improves the translation for Recurring calendar events in the Swedish version of Outlook 2016.

How to download and install the update

Microsoft Update

Use Microsoft Update to automatically download and install the update.

Download Center

This update is available for manual download and installation from the Microsoft Download Center.

If you're not sure which platform (32-bit or 64-bit) you're running, see Am I running 32-bit or 64-bit Office? Additionally, see more information about how to download Microsoft support files.

Update information


To apply this update, you must have Microsoft Outlook 2016 installed.

Restart information

You may have to restart the computer after you install this update.

More information

To determine whether your Office installation is Click-to-Run or MSI-based, follow these steps:

  1. Start an Office 2016 application.
  2. On the File menu, select Account.
  3. For Office 2016 Click-to-Run installations, an Update Options item is displayed. For MSI-based installations, the Update Options item isn't displayed.
Office 2016 Click-to-Run installation MSI-based Office 2016
The screenshot for Word click to run The screenshot for Word MSI

How to uninstall this update

Windows 10

  1. Go to Start, enter View Installed Updates in the Search Windows box, and then press Enter.
  2. In the list of updates, locate and select KB4011570, and then select Uninstall.

Windows 8 and Windows 8.1

  1. Swipe in from the right edge of the screen, and then select Search. If you're using a mouse, point to the lower-right corner of the screen, and then select Search.
  2. Enter windows update, select Windows Update, and then select Installed Updates.
  3. In the list of updates, locate and select KB4011570, and then select Uninstall.

Windows 7

  1. Go to Start, enter Run, and then select Run.
  2. Enter Appwiz.cpl, and then select OK.
  3. Select View installed updates.
  4. In the list of updates, locate and select KB4011570, and then select Uninstall.


Learn about the standard terminology that's used to describe Microsoft software updates.

The Office System TechCenter contains the latest administrative updates and strategic deployment resources for all versions of Office.

File information

The English (United States) version of this software update installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.