After KB4476976 was installed i could not yet recognize, what has happened after i rebooted: Microsoft.Windows.Cortana_cw5n1h2txyewy has been installed and since then blocks complete disks forever as part of the 'Search'-process. I tried to remove it manually, but it automatically installs itself after a reboot, even offline. It is th exact same behaviour on 2 different installations of Windows 10 LTSC 2019 x64, whereas in one i installed the Microsoft-Store; so if it is installed or not it doesn't make a difference. Both systems are configured manually in every detail for the means of cutting all wires as is possible by standard configuration options. Also i sprung back to initial on both installations and installed on those the updates manually via WSUSOfflineUpdater, while excluding KB4476976. After that i put one of the installs online and the 'Cumulative Update' was downloaded and automatically installed; after reboot Cortana is actively scanning, while all configurations stayed the same and Cortana is not available for a search by the user. It has obviously renewed the SearchUI of Cortana and scans everything it can access, without a notion or requesting permission. The other install showed the exact same behaviour as the one before, which i put online, while this second one i left offline and installed the cumulative patch via WSUSOfflineUpdater. After reboot, Cortana as part of the search-process is shown in task-manager and seems suspended. Funny is, it always shows it is suspended, once you decollapse the search-process to take a look what is running under it. Once the task-manager is not visible anymore it happily eats the drives. I came upon this while using Rufus to create Windows ToGo from LTSB 2015 N and it refused to work on any attempt with an alert of that the target disk is in use by another process. Bit by bit i checked all logically possible access paths and then stumbled over the search-process. It took a handful of tries to recognize that the disk was not rat-a-tat-tat-ing anymore as soon as i reviewed the processes running. Well, whatever, i'll dig into it, for whatever it is worth. Just wanted to let you know, possibly you experienced the same? I will now make a fresh install and try to configure Defender in forefront, so that even if the updater ignores the blocking of KB4476976 it shall be quarantined, so to say a last attempt to hinder MicroSoft with its own weapons. Oh and i am aware, that classical Windows-Search was replaced by Cortana, but the process that runs after that patch, is overly active, such that the whole system does nothing else anymore, once you are away from it, disk ressource usage peaking to the max, which you can also hear loudly. That's for it now. If you experience similar effects after applying that patch, please comment. Thanks for your interest.