We have a group of users who have contacts that were built on custom forms that contain user-defined fields as well as some contact items that may contain user defined fields just in those items. We need to convert all of our contacts to use the default message class (IPM.Contact) and then incorporate them into a third-party program (Interaction) that will once again convert them into a new message class.

The issue is that, in testing, after we convert the contacts, we lose the ability to view the custom fields and/or the data contained in those fields within the contact. (We go to All Fields, User Defined fields in the item and user defined fields in the folder and can't find the custom fields). However, if we run code to change the message class of the affected contact items back to their original message class, the custom fields and their data (along with the Interaction custom fields and data) do reappear.

Is this expected behavior? (We just want to be sure that if we run this code in a batch process on a bunch of user mailboxes, we don't end up deleting any information contained in custom fields and we don't understand where such custom data is stored and what happens when the message class association is changed.)

Any info or suggestions for other reference points would be greatly appreciated!