May 1, 2018, update for Outlook 2016 (KB4018372)

Dotyczy: Outlook 2016

This article describes update 4018372 for Microsoft Outlook 2016 that was released on May 1, 2018. 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 contains the following improvements and fixes:

  • When you use a quick step to create a task in a secondary mailbox, the task is saved to the primary mailbox and the owner is also set to the user of the primary mailbox.

  • After you migrate mailboxes from on-premise to Office 365 environment, you can log on but cannot send mails.

  • When you try to access the content of a public folder in Outlook 2016, Outlook 2016 may crash if Outlook 2016 is connected by using MAPI/HTTP

  • When a sender that is outside your organization sends an email message that has attachments to an Office 365 Modern Group, the attachments don't show in the message even though a paperclip icon displays in the message list.

  • The Outlook client may create duplicate folders for some special folders that are already in the server mailbox.

  • If you have configured an Outlook profile with multiple accounts and with the option to digitally sign email messages that are sent from them, when you open a previously saved draft email message and send it, Outlook 2016 may use the incorrect account certificate to digitally sign the message.

  • This update enables Advanced Encryption Standard (AES) algorithm with a 256-bit key length as a supported scheme when Outlook has enabled Federal Information Processing Standards (FIPS) Mode.

  • This update improves the Swiss translation.

  • This update fixes the truncation issue in the dialog box when you add a public folder for the German version.

  • Assume that you use Outlook 2016 for some time. Even if you have a reasonable memory usage, the contiguous free memory space is exhausted. This results in fragmented and non-rendering UI. This update enables the Large Address Aware (LAA) state for the 32-bit version of Outlook 2016. See KB4022148 for details.

How to download and install the update

Microsoft Update

Use Microsoft Update to automatically download and install the update.

Download Center

This update is also 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 KB4018372, 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 KB4018372, 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 KB4018372, and then select Uninstall.


Learn about the standard terminology that is 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.