This problem occurs because some of the activity fields in Microsoft CRM 1.2 are only used for certain activity types. If fields that are not related to a certain activity type are populated before you upgrade to Microsoft Dynamics CRM 3.0, custom fields are created to retain the data that is stored in the fields.
Examples of these types of fields which can be populated by using the Microsoft CRM 1.2 software development kit (SDK) include the following fields:
- DirectionCode
- ScheduledDurationMinutes
- StatusCode
- Sender
- ToRecipients
- ScheduledEnd
- ScheduledStart