Create a new PostItem in the folder.
Add a property to it with UserProperties.Add. (The default is to add it to the folder as well)
Delete the PostItem.

--
Sue Mosher, Outlook MVP
Author of Configuring Microsoft Outlook 2003
http://www.turtleflock.com/olconfig/index.htm
and Microsoft Outlook Programming - Jumpstart for
Administrators, Power Users, and Developers
http://www.outlookcode.com/jumpstart.aspx

"Jeff" wrote in message ups.com...
I want to be able to use MAPIFolder.Items.Restrict() to return me a
collection of items that my program has not yet processed. After I
process items, I mark them w/ a custom string UserProperty that I set
to a GUID.

"If you are trying to use the Find or Restrict methods with
user-defined fields, the fields must be defined in the folder,
otherwise an error will occur."-MSDN
(http://msdn.microsoft.com/library/de...HV05247704.asp)

What is the proper way to add my UserProperty to the MAPIFolder such
that I can use the Restrict method to return me the results I'm looking
for?

What query string should I pass to Restrict() that would get me all
Items that are not marked w/ my string GUID?

Thanks!
Jeff