December 2015, cumulative time zone update for Windows operating systems

Applies to: Windows Server 2012 R2 DatacenterWindows Server 2012 R2 StandardWindows Server 2012 R2 Essentials


This update supersedes and replaces the update that is described in Microsoft Knowledge Base article 3077715 that was released in August 2015. All additional time zone changes that were released as hotfixes after update 3077715 are incorporated into this update.

If you have already deployed update 3077715, read the descriptions of the specific time zone changes in the "General changes made by this update" section in this article to determine whether you must deploy this update immediately. If your system isn't affected directly, you can schedule deployment at the next available opportunity.

We recommend that you deploy the most current Windows cumulative time zone update to guarantee the consistency of the time zone database on all systems.


  • Before you apply the update that is described in this article, be aware of potential issues that may affect Microsoft Outlook. For more information about these issues, click the following article number to go to the article in the Microsoft Knowledge Base:

  • Cumulative time zone updates contain only data that has changed for a specific region or that was added to maintain parity with other operating system versions. Therefore, if a time zone-related registry subkey is deleted, some original values may not be restored after you apply the cumulative zone update.

    Note We do not recommend that you delete any registry subkeys that are related to time zones. On a computer that has incomplete time zone subkeys, first restore the time zone subkeys from a known good backup. Then, apply the update.

More Information

  • The update that is described in this article changes the time zone data to accommodate daylight saving time (DST) changes in several countries.

    This is a cumulative update rollup that includes all previous Windows time zone changes. For more information about how DST changes may affect other Microsoft products, go to the following Microsoft websites:

  • When you apply this update, you may receive a message that resembles the following:

    Update cannot be installed as a newer or same time zone update has already been installed on the system.
    This message indicates that either you have already applied the correct update or Windows Updates or Microsoft Update has automatically installed this update. No additional action is required to update the Windows operating system.

File information

For a list of the files that are provided in this cumulative update, download the file information for cumulative update 3112148.