Microsoft KB Archive/933344

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Article ID: 933344

Article Last Modified on 8/15/2007


  • Windows Mobile 5.0 for Pocket PC


Recent updates to Microsoft Windows Mobile 5.0 to enable changes to daylight saving time (DST) have introduced a bug in the Clock & Alarms tool. The time zone may change unexpectedly on a Windows Mobile 5.0-based device. You can recover the Windows Mobile 5.0-based device from the unintended change. OEMs can lessen the problem by presetting the registry with values to set the default visiting city.


When you open the Clock & Alarms tool or an application that uses the time services of a Windows Mobile 5.0-based device, you notice that the time zone on the device has changed. The time zone has been set to the DST time zone that is currently set for the Visiting option of the Clock & Alarms tool.


This problem was introduced in the Clock & Alarms Tool in Windows Mobile 5.0 Adaptation Kit Update 3.0. This problem occurs because of an error in the time zone checking. This error causes Windows Mobile to update the Home time zone to the Visiting time zone. This problem occurs when the Visiting time zone is a United States DST time zone.

This problem is present in the following Windows Mobile 5.0 Adaptation Kit updates:

  • Windows Mobile 5.0 Adaptation Kit Update 3.4
  • Windows Mobile 5.0 Adaptation Kit Update 3.3
  • Windows Mobile 5.0 Adaptation Kit Update 3.2
  • Windows Mobile 5.0 Adaptation Kit Update 3.1
  • Windows Mobile 5.0 Adaptation Kit Update 3.0


If you are an OEM, and you are using an Adaptation Kit update that is listed in the “Cause” section, you can use the following workaround for this problem.

To help your device users avoid the problem, preset the default visiting city when you build the image for the Windows Mobile 5.0-based device. To do this, include the following registry entry in the Windows Mobile 5.0-based device’s initial registry:


Note The city code 415 (19F hexadecimal) indicates Taiwan. To avoid this problem, use a city code for any city that is not located in a time zone that is listed in the “More Information” section. For a list of valid city codes, see the “Home and Visiting Time Zones Settings” section of the Adaptation Kit update documentation.

When an OEM uses this workaround, a user who selects a visiting city in one of the previously listed time zones will still experience this problem. The user can work around the problem by following the instructions in the following Microsoft Knowledge Base article:

932472 The Home time zone setting in the Clock & Alarms tool changes to the Visiting time zone setting on a Windows Mobile 5.0-based device


This problem is resolved in Windows Mobile 5.0 Adaptation Kit Update 3.5.


The changes to the time zone settings occur when the Clock & Alarms tool is opened. However, the Clock & Alarms tool settings that are displayed do not update when this problem occurs. Therefore, you may not notice the change until the next time that you open the Clock & Alarms tool.

This problem only occurs after January 1, 2007. Additionally, this problem only occurs when the Visiting time zone is set to a United States time zone that observes DST. The following United States time zones observe DST:

  • GMT-9 Alaska
  • GMT-8 Pacific US
  • GMT-7 Mountain US
  • GMT-6 Central US
  • GMT-5 Eastern US

Some localized versions of Windows Mobile 5.0 use a default visiting city that is located in the GMT-8 Pacific US time zone. A user will experience this problem on a device that is running one of these localized versions unless the OEM uses the workaround that is described in the “Workaround” section. An OEM should check the Clock & Alarms tool in the localized build. If the visiting city that is selected is located in one of the previously listed time zones, this problem will occur.

Steps to reproduce the problem

  1. Tap Start, and then tap Settings.
  2. Tap the System tab, and then tap Clock & Alarms.
  3. Tap Visiting, and then select GMT-8 Pacific US in the drop-down list.
  4. Tap OK.
  5. In the Settings dialog box, tap Yes to confirm the changes.
  6. Tap Clock & Alarms. Notice that the time settings appear to be correct.
  7. Tap OK.
  8. Tap Clock & Alarms to reopen the Clock & Alarms tool. Notice that the home time zone has changed.

Additional query words: DST time zone

Keywords: kbtshoot kbbug kbprb KB933344