May 3, 2016, update for Outlook 2016 (KB3115101)

Van toepassing: Outlook 2016

This article describes update KB3115101 for Microsoft Outlook 2016, which was released on May 3, 2016. 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

  • Adds Defenders of Ukraine Day to the Outlook holiday list for Ukraine in Outlook 2016.
  • Translates the Defenders of Ukraine Day into the MSI-supported UI languages.
  • Updates some translations for some features in Outlook 2016 in multiple languages to make sure that the meaning is accurate.
  • Fixes the following issues:
    • When you try to create a new profile in cached mode in Outlook 2016, you receive the following error message if the .ost file name contains an MS-DOS device driver name:
      Cannot open your default e-mail folders. Unknown Error.
      For the list of default device driver names, see the "MORE INFORMATION" section in article KB74496.
    • Online archive and public folders may disappear for a profile in Outlook 2016.
    • Assume that Outlook 2016 connects to an Exchange server in an intranet by using the MAPI over HTTP transport protocol. If you open the Connection Status dialog box, the Authn column displays Error* but not AutoLogon*.
    • Time window settings in the Sync Slider window do not match those available in the Outlook 2016 Administrative Template.
    • Outlook 2016 ignores the non-policy SyncWindowSetting key if the disk size is smaller than 64 GB.

      Note See KB3115009 for more information.
    • Outlook 2016 immediately deletes or duplicates email messages for POP3 accounts regardless of email settings.

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 what 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 installationMSI-based Office 2016
The screenshot for Word click to run The screenshot for Word MSI


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 global version of this update has the file attributes (or later file attributes) that are listed in the following table.