This error KB4592438 has been going on in the past three days. when I am trying to install the update KB4592438 for Windows 10 20H2. It's downlaoded without any problem but the installation fails.
Any thoughts on how to fix this please ?.

Is there any detail as to why it is failing? An error message?
There's a long thread in the Microsoft Community about this update failing -- https://answers.microsoft.com/en-us/windows/forum/windows_10-update/cumulative-update-december-2020-kb4592438-failed/b33fd201-0a6f-4625-8e9c-e7494756bb46?auth=1

Has the January cumulative update installed? If so, ignore the December update.

-steve

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stephen boots
Microsoft MVP 2004 - 2020
"Life's always an adventure with computers!"

You can easily fix this error on your PC and install the update. A few days back I also went through the same error, then this article helped a lot in getting rid of this issue. Here is the link to that article: Windows Update KB4592438 Failed to Install
I hope it will help you to resolve the problem.

Note that the article provides generic steps to resolve various Windows Update errors and any one of them could resolve a problem with Windows Update legitimately. I do recommend avoiding the last entry on that page, purporting to be an easy solution using the tool that sounds like a registry cleaner type tool. Many of those tools cause more damage than they repair and are not likely to be free.
A little research on the tool suggested as the easy fix leads to a product that is exactly as I suspected... It is not likely going to fix anything and it will cost you money and then potential troubles to remove the "tool." See - https://answers.microsoft.com/en-us/windows/forum/windows_10-security/warning-advanced-system-repair-pro-safecart/e89f3e72-aa3e-4328-934c-a155a1a2de40?auth=1 and https://answers.microsoft.com/en-us/windows/forum/windows_10-networking/advanced-system-repair-pro/f47d2cad-6a7f-4b72-919b-db122fcb2adf

_________________
stephen boots
Microsoft MVP 2004 - 2020
"Life's always an adventure with computers!"

Thanks admin!!! I really appreciate your help although this helps to solve the erorr - https://appuals.com/cumulative-update-december-2020-kb4592438-failed-to-install/

Which steps in the article solved the problem for you?

_________________
stephen boots
Microsoft MVP 2004 - 2020
"Life's always an adventure with computers!"