Outlook 2k3

By wesley.chin ·
With the daylight savings change, the computers seem to be running fine. But I am curious why there is a separate update that MS has available for Outlook 2k3. Is it needed even when the computer updates through Microsoft Update?

This conversation is currently closed to new comments.

Thread display: Collapse - | Expand +

All Answers

Collapse -


by scott_heath In reply to Outlook 2k3

Why the Time Zone Data Update Tool is required
Calendar items are created in Outlook by using Coordinated Universal Time (UTC) format. UTC is an international standard 24-hour timekeeping system. Time zone information for Outlook is obtained from the Windows operating system in which the calendar items are created and is obtained at the time that the calendar items are created.

For example, an 8:00 A.M. appointment on October 26, 2007 in Redmond, Washington is stored in Outlook as UTC 4:00 P.M. In this case, DST has not yet started, and Redmond time is eight hours behind UTC.

When an update is applied to the Windows operating system to accommodate the new DST definitions, the computer?s local time is changed to the extended DST time. However, the UTC is not adjusted when the local time on the computer is adjusted. Therefore, calendar items that are added to Outlook during the extended DST period are off by one hour.

The Time Zone Data Update Tool is intended to update the targeted Outlook data store to correctly reflect the new time zone rules. A data store can be a .pst file, an .ost file, or the user?s Exchange mailbox if the user is running in Online mode.

For example, consider the following scenario: ? Windows has not been updated for the extended DST period.
? The Time Zone Data Update Tool has not been run on the computer.
? An appointment is scheduled for 8:00 A.M. on October 15, 2007 in Redmond.
? During the extended DST period, the start time for the appointment is set at 9:00 A.M. instead of 8:00 A.M.
In this scenario, the appointment is originally stored in Outlook as 4:00 P.M. UTC. To calculate the local time in Redmond, the "UTC - 8 hours" formula is used. In this case, 4:00 P.M. UTC minus 8 equals 8:00 A.M.

However, after the DST update is applied to Windows, local time is calculated by using the "4.00 P.M. - 8 hours + 1 hour" formula for DST. Therefore, the time in the appointment is set to 9:00 A.M. To correct this issue, the Time Zone Data Update Tool must be run on the computer.

Hope this helps.

Related Discussions

Related Forums