This article applies to Domain Time.

Last updated: 5/23/2002

Problem

Event Viewer shows the message Event ID 49, "An unexpected error occurred while trying to start the server. The port may be in use" on startup or if you try to start the Windows Time (W32Time) service manually.

Details

Both Domain Time II Server and the Windows Time (W32Time) service are trying to listen for NTP requests on UDP port 123 (that is, both services are trying to be an NTP server). Only one process may be an NTP server on a machine. Whichever service happens to start first will "own" the port, and the other one will generate an error indicating that the port is already in use.

Normally, the Windows Time (W32Time) service does not try to be an NTP server. You may set a registry entry to force the service to be an NTP server, but there is no registry entry to force it not to be an NTP server. Instead, the service decides whether or not to be an NTP server based on the domain role of the machine where it finds itself running. (See Q223184 in the Microsoft Knowledgebase for more information.)

When the Windows Time (W32Time) service runs on a Windows 2000 Domain Controller (DC), the service will try to become an NTP server even if you have the service set to NoSync (see KB2001.002 for information on W32Time service roles).

Solution

1. If your machine is a Windows 2000 DC and also a Cluster Server, you must allow Windows Time (W32Time) to be the NTP server. Use Domain Time Server's control panel applet to turn off the NTP/SNTP protocol. Stop and restart the Domain Time Server service, then stop and restart the Windows Time service.

2. If your machine is not a Cluster Server, you should just disable the Windows Time service. If you want to run both Domain Time Server and the Windows Time service, see KB2001.002 and also Co-existing with Win2000 Time Service for instructions and precautions.