Microsoft small business knowledge base

Article ID: 2687252 - Last Review: March 4, 2013 - Revision: 5.0


Microsoft is aware of a potential system unresponsiveness issue that may be caused by using the RealTimeIsUniversal registry entry for the Daylight Saving Time (DST) changeover.


A hotfix is available to resolve this issue in Windows Server 2008, Windows 7, and Windows Server 2008 R2.  For more information, click the following article number to view the article in the Microsoft Knowledge Base:
2800213  ( ) High CPU usage during DST changeover in Windows Server 2008, Windows 7, or Windows Server 2008 R2
We strongly recommend that you not use the RealTimeIsUniversal registry entry. This issue does not occur if you do not use this entry.

We recommend that you remove the RealTimeIsUniversal value from the registry or set its value to 0. This will prevent the system from becoming unresponsive during the DST changeover. To make this change, follow these steps.

Warning This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

322756  ( ) How to back up and restore the registry in Windows
To have us set the RealTimeIsUniversal value to 0 for you, go to the "Fix it for me" section. If you prefer to set the RealTimeIsUniversal value to 0 yourself, go to the "Let me fix it myself" section.

Fix it for me

To set the RealTimeIsUniversal value to 0 automatically, click the Fix it button or link. Then click Run in the File Download dialog box, and follow the steps in the Fix it wizard.

Fix this problem
Microsoft Fix it 50851

  • This wizard may be in English only. However, the automatic fix also works for other language versions of Windows.
  • If you are not on the computer that has the problem, save the Fix it solution to a flash drive or a CD and then run it on the computer that has the problem.

Then, go to the "Did this fix the problem?" section.

Let me fix it myself

  1. Start Registry Editor, and then locate the following subkey:
  2. Select the RealTimeIsUniversal entry.
  3. On the Edit menu, click Modify.
  4. In the Value data field, type 0.
  5. Exit Registry Editor.
  6. Restart the computer.

Did this fix the problem?

  • Check whether the problem is fixed. If the problem is fixed, you are finished with this section. If the problem is not fixed, you can contact support ( .
  • We would appreciate your feedback. To provide feedback or to report any issues with this solution, please leave a comment on the "Fix it for me ( " blog or send us an email ( message.

Applies to
  • Microsoft Windows XP Home Edition
  • Microsoft Windows XP Professional
  • Microsoft Windows XP Service Pack 3
  • Windows Vista Business
  • Windows Vista Enterprise
  • Windows Vista Home Premium
  • Windows Vista Ultimate
  • Windows Vista Service Pack 1
  • Windows Vista Service Pack 2
kbfixme kbmsifixme KB2687252
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