When a virtualized domain controller is running in a guest operating system on a host server that is running Windows Server 2008 with Hyper-V, and the Windows Time Service (W32Time) synchronizes with a primary domain controller, the following events may be logged in the System log on the virtualized domain controller:
Event Type: Warning Event Source: W32Time Event Category: None Event ID: 24 Date: Date Time: Time User: N/A Computer: ComputerName Description: Time Provider NtpClient: No valid response has been received from domain controller Yourpdc.forestroot.com after 8 attempts to contact it. This domain controller will be discarded as a time source and NtpClient will attempt to discover a new domain controller from which to synchronize.
Event Type: Error Event Source: W32Time Event Category: None Event ID: 29 Date: Date Time: Time User: N/A Computer: ComputerName Description: The time provider NtpClient is configured to acquire time from one or more time sources, however none of the sources are currently accessible. No attempt to contact a source will be made for 15 minutes. NtpClient has no source of accurate time. For more information, see Help and Support Center at http://support.microsoft.com.
Event Type: Information Event Source: W32Time Event Category: None Event ID: 38 Date: Date Time: Time User: N/A Computer: ComputerName Description: The time provider NtpClient cannot reach or is currently receiving invalid time data from Yourpdc.forestroot.com.
If you enable Windows Time Services Debug logging on the domain controller, information that resembles the following is logged in the Debug log:
149040 14:15:14.2970940s - Logging information: The time service is now synchronizing the system time with the time source VM IC Time Synchronization provider.
On a host server that is running Windows 2008 with Hyper-V, virtualized domain controllers that are running on a guest operating system are allowed to synchronize their system clocks with the clock of the host operating system. The events that are listed in the "Symptoms" section are recorded in the System log because domain controllers have their own time synchronization mechanism. If domain controllers synchronize time from their own source and synchronize time from the host, the domain controller time can change frequently. Because many domain controller tasks are tied to the system time, a jump in the system time can cause lingering objects to be left in caches, and may cause replication to stop.
To resolve this issue, disable time synchronization on the host by using Integration Services, and then configure the virtualized domain controller to accept the default Windows Time Service (W32time) domain hierarchy time synchronization.