A strange set of messages—event ID 2405 (polling MS mail queue) followed by event ID 2406 (MS mail queue is empty. Sleeping...)—has started popping up on my Windows 2000 Service Pack 3 (SP3) server, which runs Microsoft Exchange Server 5.5 SP4. Everything on the system seems to work properly, but the messages repeat every minute and are filling up my logs. I can't find any information about these messages. Do you have any suggestions?

I've seen situations such as this many times, and such messages are almost always the result of some third-party application running on the machine. The messages have a definite consistency (i.e., they are logged every minute), so the good news is that you'll know the minute—literally—you lick the problem. To determine the errors' source, I recommend that you use the Control Panel Services applet to stop the system's services one by one, waiting a few minutes after stopping each to determine whether the error messages cease—and thereby determining which service is the culprit. You can then address the problem directly (e.g., contact the application vendor, remove the service).