I have a domain controller configured to use time.windows.com (with 0x09 flags set). I've noticed that frequently the systems' clock is fast - it varies from 10 minutes to even 45 minutes. I always have to keep resetting the system date/time back to what it should be.

When I run "w32tm /query /source" it tells me it's using time.windows.com, and obviously I trust Microsoft not to serve incorrect times, but why is my server's clock fast?

EDIT:

There are a few Time-Service events in the System log:

Event ID: 142

Message: The time service has stopped advertising as a time source because the local clock is not synchronized.

Event ID: 139

Message: The time service has started advertising as a time source.

These two messages appear in pairs every hour or so. Event 142 appears 14 to 16 minutes after 139 appears.

Going back a few months, these events appear:

Event ID: 35

Message: The time service is now synchronizing the system time with the time source time.windows.com,0x9 (ntp.m|0x9|0.0.0.0:123->65.55.21.21:123).

Event ID: 37

Message: The time provider NtpClient is currently receiving valid time data from time.windows.com,0x9 (ntp.m|0x9|0.0.0.0:123->65.55.21.21:123).

Event ID: 47

Message: Time Provider NtpClient: No valid response has been received from manually configured peer time.windows.com,0x9 after 8 attempts to contact it. This peer will be discarded as a time source and NtpClient will attempt to discover a new peer with this DNS name. The error was: The time sample was rejected because: The peer is not synchronized, or it has been too long since the peer's last synchronization.

These three events only appear once in the log, back in October.