ErrorInvalidExtendedProperty: This error indicates that the Destination rejected an item because it has invalid MAPI properties. Most Exchange items have hundreds of MAPI properties. Finding the exact combination of values that is causing the Destination to reject the the item as invalid is therefore impossible. In most cases, we find that the offending items are either corrupt, were created by misbehaving third-party applications, or are very old items whose values are no longer valid for more recent releases of Exchange Server.
We recommend the following:
- Log the subject of failed items.
- Retry failed items (subjects will be logged).