Сообщение от
RTF MSDN;
Each folder has an ID field called Folder.StoreId, the value of which is the same for all the folders in a particular message store. Each folder also has a unique Entry ID field.
When using the getItemFromID method to retrieve an item based on its ID, you should specify both the EntryID of the item and the StoreID of the folder. If you do not specify the StoreID, getItemFromID searches the default message store.