Known Issue with February 9, 2021 servicing stack update (SSU) KB4601392 | Windows Server 2016 | Windows 10 Version 1607
Many of you might experience after installing the SSU KB4601392, installation of the Cumulative Update from Windows Update might not progress past 24%.
Important – There is a Known Issue that halts the installation progress of the February 9, 2021 security update. To address this issue, Microsoft have released a new servicing stack update (SSU), KB5001078. You must install this new SSU before installing the February 9, 2021 security update.
KB4601392 has been removed and will no longer be offered to devices. This issue was resolved in KB5001078.
More details here – https://support.microsoft.com/en-us/topic/february-9-2021-kb4601318-os-build-14393-4225-c5e3de6c-e3e6-ffb5-6197-48b9ce16446e