Summary

This update supersedes and replaces the update that is described in Microsoft Knowledge Base article 3013410 that was released in December 2014. All additional time zone changes that were released as hotfixes after update 3013410 was released are incorporated in this update.

If you have already deployed update 3013410, read the descriptions of the specific time zone changes that are addressed in this article to determine whether you must deploy this update immediately. If no systems are 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.

Important

  • 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:

    931667 How to address time zone changes by using the Time Zone Data Update Tool for Microsoft Office Outlook

  • 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 website:

General information about DST For more information about how DST changes may affect other Microsoft products, click the following article number to go to the article in the Microsoft Knowledge Base:

914387 How to configure daylight saving time for Microsoft Windows operating systems Note 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.

How to obtain this update To get the stand-alone package for this update, go to the Microsoft Update Catalog website.

For more information about how to download Microsoft support files, click the following article number to go to the article in the Microsoft Knowledge Base:

119591 How to obtain Microsoft support files from online services Virus-scan claim

Microsoft scanned these files for viruses. Microsoft used the most current virus-detection software that was available on the date that the files were posted. The files are stored on security-enhanced servers that help prevent any unauthorized changes to the files.

Prerequisites Windows 8.1 and Windows Server 2012 R2

To apply this update, you must have update 2919355 installed. For more information about how to obtain this update, click the following article number to go to the article in the Microsoft Knowledge Base:

2919355 Windows RT 8.1, Windows 8.1, and Windows Server 2012 R2 update: April 2014 Windows 8 and Windows Server 2012

No prerequisites are required to apply this update.

Windows 7 and Windows Server 2008 R2

No prerequisites are required to apply this update. The same package installs both on the RTM version as well as the Service Pack 1 versions of Windows 7 and Windows Server 2008 R2. For more information about how to obtain a Windows 7 or a Windows Server 2008 R2 service pack, click the following article number to go to the article in the Microsoft Knowledge Base:

976932 Information about Service Pack 1 for Windows 7 and for Windows Server 2008 R2 Windows Server 2008

To apply this update, you must be running Windows Vista Service Pack 2 (SP2) or Windows Server 2008 SP2.

For more information about how to obtain a Windows Server 2008 service pack, click the following article number to go to the article in the Microsoft Knowledge Base:

968849 How to obtain the latest service pack for Windows Server 2008

Registry information To apply this update, you do not have to make any changes to the registry.

Restart requirement You must restart the computer after you install this cumulative update.
 

The following changes were made since the previous Windows cumulative time zone update:

  • Pacific SA Standard Time
    For 2015 and going forward, Chile will remain in DST. (No DST change will be observed.) Therefore, the UTC offset for Chile is updated to UTC-3:00, and the display name of the "Pacific SA Standard Time" time zone is updated to "(UTC-3:00) Santiago." (3039024)

  • Iran Standard Time
    Iran follows the Persian calendar. This cumulative update corrects the DST data for "Iran Standard Time" in Windows for the years 2015 through 2024. (3049874)

  • Eastern Standard Time (Mexico)
    The Mexican state of Quintana Roo has moved from UTC-6:00 to UTC-5:00 "(UTC-05:00) Chetumal." This time zone is newly introduced and will not observe DST. (3049874)

  • Montevideo Standard Time
    On June 30, 2015, the Uruguayan government decided to abolish the observance of daylight saving time. This put the country into the UTC-03:00 time zone all year round.

  • Ulaanbaatar Standard Time
    Mongolia will observe DST starting in 2015. DST for Mongolia starts on the last Saturday of March at 02:00 and ends on the last Saturday of September at 00:00. The following DST rules will be observed. (3049874)

    Time zone key name

    Display name

    DST start

    DST end

    Mongolia Standard Time

    (UTC+8:00) Ulaanbaatar

    Last Saturday of March at 02:00:00.000

    Last Saturday of September at 00:00:00.000

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