The system time lags when you restart a Windows Vista-based computer that supports High Precision Event Timer

A computer that is running Windows Vista supports High Precision Event Timer (HPET). When you restart the computer, the system time that appears on the clock lags behind the actual time. After you restart the computer several times, the system time lags behind the actual time even more.

This problem occurs because a problem in Windows Vista causes a loss to the system time of approximately 0.85 seconds every time that you restart the computer.

If you are connected to the Internet

Service pack information

To resolve this problem, obtain the latest service pack for Windows Vista. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Hotfix information

To resolve this problem, install hotfix 929637. After you install this hotfix, a small time loss still occurs after you restart the computer. However, the Windows Time Service (WTS) adjusts the time automatically. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

If you are not connected to the Internet

If the computer is not connected to the Internet, the Windows Time Service cannot adjust the time automatically. Therefore, a small time loss may be noticed even if you install hotfix 929637. To work around this problem if the computer is not connected to the Internet, disable the Windows Time Service. To do this, follow these steps:

1. Click Start
   Collapse this imageExpand this image

   
   , type services.msc in the Start Search box, and then click services.msc in the Programs list.
   
   
   Collapse this imageExpand this image

   
   If you are prompted for an administrator password or for confirmation, type your password, or click Continue.
2. Double-click Windows Time.
3. Click Stop.
4. Select Disabled in the Startup type box.
5. Click Apply.

When you disable the Windows Time Service, the small time loss does not occur. However, we do not recommend that you disable the Windows Time service in an environment where the computer is connected to the Internet. When an Internet connection is available, Windows will contact a network time protocol server (NTP) to update the system clock.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. This problem was first corrected in Windows Vista Service Pack 1.

For more information about the terms that are used to describe software updates, click the following article number to view the article in the Microsoft Knowledge Base: