When you activate Microsoft Office Trial, the date from your computer's clock is recorded as the activation start date. This dialog appears when Microsoft Office detects a discrepancy between the expected date and the date reported by your system clock.
To manually correct the clock date (and time zone, if necessary), click the Adjust Clock button in this dialog to launch the date and time control panel application and make the change.
If you have an Internet connection and want to validate that your clock has the correct setting, click the Verify Date button. This will connect you to a Microsoft server where the time and date for your currently time zone setting will be verified. If your computer clock is set incorrectly, then you should manually correct the clock date and time zone by clicking the Adjust Clock button, as described above. If your computer clock is validated by the Verify Date button, this dialog will not be displayed again.
If you don't correct the clock settings, Microsoft Office will go into Reduced Functionality Mode. In that mode you will not be able to save modifications to documents or create a new document, and additional functionality may be reduced.