Migration Agent for Exchange (MAgE) shows the following error in the log file:
Error System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.
at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
at Dell.MigrationManagerForExchange.Shared.Database.DictExtensionMethods.ToMailboxProcessingInfo(Dictionary`2 coll, Nullable`1 stage)
at Dell.MigrationManagerForExchange.Shared.Database.SqlMailboxProcessingInfoStorage.Load(Int32 mailboxId, Int32 syncType)
at Quest.MigrationManager.Exchange.Agent.QTaskManager.MailboxToBeSkippedCheckParent(Int32 mailboxId, IQCollection collection, String& reason)
at Quest.MigrationManager.Exchange.Agent.QTaskManager.MailboxToBeSkipped(Int32 mailboxId, IQCollection collection, ActionType actionType, String& reason)
at Quest.MigrationManager.Exchange.Agent.QTaskManager.CreateTask(IAssignment asmnt)
at Quest.MigrationManager.Exchange.Agent.QTaskManager.PickNextAssignment()
at Quest.MigrationManager.Exchange.Agent.QTaskManager.MailboxThread()