The issues seem linked to the use of antivirus products from specific manufacturers, including Avast, AVG, and Sophos, with Sophos coming in for particular problems. Microsoft has apparently blocked update distribution to individuals with Sophos installed as a result. Sophos has published its own blog post on this topic, walking individuals through how to uninstall the Microsoft updates if they also use Sophos Endpoint. Sophos claims that specific updates KB4493467, KB4493446, KB4493448, KB4493472, KB4493450 and KB4493451 are responsible for these problems