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You upgrade Windows XP Service Pack 2 (SP2) to Windows Vista or to Windows Vista Service Pack 1 (SP1). However, the following Windows Time Synchronization service (W32Time)-related registry settings are not updated to the default Windows Vista values.

Default registry settings in Windows XP

Registry location	Value name	Value type and data
HKEY_LOCAL_MACHINE SYSTEM CurrentControlSet Services W32Time Config	LargePhaseOffset	dword:00138800 (Decimal:1280000)
HKEY_LOCAL_MACHINE SYSTEM CurrentControlSet Services W32Time Config	SpikeWatchPeriod	dword:0000005a (Decimal:90)
HKEY_LOCAL_MACHINE SYSTEM CurrentControlSet Services W32Time TimeProviders NtpClient	EventLogFlags	dword:00000000 (Decimal:0)
HKEY_LOCAL_MACHINE SYSTEM CurrentControlSet Services W32Time TimeProviders NtpServer	Enabled	dword:00000001 (Decimal:1)

Default registry settings in Windows Vista

Registry location	Value name	Value type and data
HKEY_LOCAL_MACHINE SYSTEM CurrentControlSet Services W32Time Config	LargePhaseOffset	dword:02faf080 (Decimal:50000000)
HKEY_LOCAL_MACHINE SYSTEM CurrentControlSet Services W32Time Config	SpikeWatchPeriod	dword:00000384 (Decimal:900)
HKEY_LOCAL_MACHINE SYSTEM CurrentControlSet Services W32Time TimeProviders NtpClient	EventLogFlags	dword:00000001 (Decimal:1)
HKEY_LOCAL_MACHINE SYSTEM CurrentControlSet Services W32Time TimeProviders NtpServer	Enabled	dword:00000000 (Decimal:0)

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Important 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:

To manually change these settings to the default Windows Vista values, follow these steps:

1.	Click Start, type regedit in the Start Search box, and then click regedit in the Programs list. If you are prompted for an administrator password or for confirmation, type the password, or click Continue.
2.	Locate and then click the following registry subkey: HKEY_LOCAL_MACHINE SYSTEM CurrentControlSet Services W32Time Config
3.	Right-click LargePhaseOffset, and then click Modify.
4.	In the Value data box, type 02faf080, and then click OK.
5.	Right-click SpikeWatchPeriod, and then click Modify.
6.	In the Value data box, type 00000384, and then click OK.
7.	Locate and then click the following registry subkey: HKEY_LOCAL_MACHINE SYSTEM CurrentControlSet Services W32Time TimeProviders NtpClient
8.	Right-click EventLogFlags, and then click Modify.
9.	In the Value data box, type 1, and then click OK.
10.	Locate and then click the following registry subkey: HKEY_LOCAL_MACHINE SYSTEM CurrentControlSet Services W32Time TimeProviders NtpServer
11.	Right-click Enabled, and then click Modify.
12.	In the Value data box, type 0, and then click OK.
13.	Exit Registry Editor, and then restart the computer.

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Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the Applies to section.

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Value name	Description
LargePhaseOffset	Specifies the time offset, in tenths of a microsecond (A tenth of a microsecond is equal to 10 to the power of -7). Times that are larger than or equal to this value are considered suspicious and possibly incorrect.
SpikeWatchPeriod	Specifies how long, in seconds, that a suspicious time offset must persist before it is accepted as correct.
EventLogFlags	Stores configuration data for the policy setting, Configure Windows NTP Client.
Enabled	Indicates whether the NtpServer provider is enabled in the current Time Service.

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