The elder Dempster continued to make decisions that were the ruin of the family. Clan feuding was an expensive activity from which every clan suffered. The elder Thomas had already lost much of his estate to pay for feuds with Clan Currer and Clan Grant. He decided now to sell the estate at Muiresk to the Earl of Erroll to prevent his eldest son from ever inheriting it. The earl took advantage of some fine print in the law, now obscure, to evade payment.