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Important update

We have received reports that Armenia and Ukraine have canceled their proposed changes. According to reports inĀ Rada and Kyivpost, Ukraine will not stay on permanent summer time and instead will fall back to winter time on October 30, 2011 as originally scheduled. If these reports become the plan of record, customers in Armenia and Ukraine will not have to adjust time zone settings on their computers that are running Windows. This Microsoft Knowledge Base article will be updated when Microsoft has confirmation about this decision.


Time information in Windows for time zones in Ukraine [(UTC+02:00) Helsinki, Kyiv, Riga, Sofia, Tallinn, Vilnius], Belarus [(UTC+02:00) Minsk], and Armenia [(UTC+04:00) Yerevan] will be incorrect after October 30, 2011.

More Information

Ukraine, Belarus, and Armenia have decided to discontinue daylight saving time in 2011. According to the current Windows time zone rules, daylight saving time (summer time) is (UTC+3:00) in Belarus and Ukraine and (UTC+5:00) in Armenia. Summer time is scheduled to end on October 30, 2011 and move to winter time, which is (UTC+2:00) in Belarus and Ukraine and (UTC+4:00) in Armenia. According to the latest changes, they will remain on summer time (UTC +3:00) indefinitely and will not "fall back" to winter time.

The native time zones for the affected countries will be updated in the next planned cumulative Windows time update in December 2011. No hotfix is planned for release in the interim. Users in these time zones should move to the following alternative suggested time zones:

  • (UTC +3:00) Kaliningrad

  • (UTC +5:00) Tashkent

Note To move to the "(UTC +3:00) Kaliningrad" time zones, customers must first install the August 2011 cumulative time zone update for Windows operating systems.

A new time zone will be created for Ukraine and Belarus in the December 2011 Windows time cumulative update, which users can move back to.





Affected country

Native time zone

Standard time

Daylight saving time

Workaround time zone (no daylight saving time)


(UTC+02:00) Minsk



(UTC +3:00) Kaliningrad


(UTC+02:00) Helsinki, Kyiv, Riga, Sofia, Tallinn, Vilnius



(UTC +3:00) Kaliningrad


(UTC+04:00) Yerevan



(UTC +5:00) Tashkent

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

2570791 August 2011 cumulative time zone update for Windows operating systems

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