Periodically, market data servers send Investor/RT a time of day notification to ensure that the user's computer clock is in sync with the server. When the time of day sent by the server, which we consider authoritative, is offset more than a second or two from the current time of day on your computer clock, this message will appear. It indicates a condition that should be corrected. It is important that your computer clock be set to the exact hour/minute/second every day. Investor/RT monitors the time stamps of incoming trades comparing them with the computer clock to see how much latency there is between the occurrence of a trade and time Investor/RT receives it. Obviously if your computer clock is say 5 seconds fast, Investor/RT may incorrectlly determine that I/RT is falling behind real-time data reception. Similarly, if your computer clock is 5 seconds slow, then Investor/RT could incorrectly determine that the data feed is current when it fact it is up to 5 seconds behind in actually. Synchronizing your computer clock daily with a time server is the soluiton. The Clock Offet messages are just a reminder that your clock appears to be offset more than a few seconds from the server.
To correct this, Windows users double-click on the clock in the task bar to bring up the Date and Time Properties window, click the Internet Time tab, and do an automatic update of the computer clock by clicking Update Now. The update takes approximately 10 seconds to complete.
Macintosh OS X synchronizes the clock with a time server automatically if you elect this feature. There is no Update Now option. If you experience this offset message, go to the System Preferences, choose the Date Time preferences panel and check the Set Date and time automatically checkbox and try a different time server. This will cause OS X to sync the clock and the offset message should then cease to appear once per minute.