The MAgE agent may log the following sequence when processing mailbox folders:
2015-01-20 08:33:52.2657 Px13DC TxE4 A109 C8 M10 Error System.ArgumentException: An item with the same key has already been added.
at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
at Quest.MigrationManager.Exchange.MigrationConnectors.EwsSyncConnector.<GetChangedItemsFTS>d__1c.MoveNext()
at Quest.MigrationManager.Exchange.MigrationConnectors.GenericSyncConnector.ProcessChangedItemsCache(String folderId, String alienFolderId)
at Quest.MigrationManager.Exchange.MigrationConnectors.GenericSyncConnector.SyncFolderItems(String folderId, String alienFolderId, Boolean& moreFolderChangesAvailable)