Windows update version 20h2 is stuck at 20% installing

Hi,

When having troubles with some update, install it manually, much more reliable. You can download it from here, I put the link to the kb5001330:

https://www.catalog.update.microsoft.com/Search.aspx?q=KB5001330

You probably want the "2021-04 Cumulative Update for Windows 10 Version 2004 for x64-based Systems (KB5001330)" for "Windows 10, version 1903 and later", size "555,4 MB. Notice that when searching you can get reapeated results with different names, but at the end is the same MSU file.

Launch the installer, it also seems to stuck soon, let it to work, it then skips to the end and shows the restart dialog.

After, launch again the Windows Update to install the other ones, there should be no problems. There is another one related, optional to install, the kb5001391 one. This one also takes long, and after reaching 100%, it backs to 0% and installs again, it is rare but it ends installing fine. And if not, can always to download and install it manually just like the kb5001330.

I had the update stuck at 61% initially. I believed it was partly due to my bios clock not keeping time correctly. Corrected that but still had to google for other fixes after it got stuck again. After numerous attempts and downloading the update assistant, it got to 99%. I couldn't get past 99% over 2 days until I uninstalled and deleted my Conexant HD audio driver. That did the trick... finally. There could be a whole host of reasons why updates get stuck. It's simply too frustrating and time consuming for me...I'm prepared to ditch Microsoft for Apple.

Check your Win version. It might not be the latest 20H2. I got the Update Assistant stuck at 99% too and the Update and Security telling me I am up to date. However I am still on the old version. I subsequently found that my Conexant HD audio driver was interfering with the update. After I uninstalled and deleted that, it worked. 

As other poster mentioned in this thread, the cause was his graphics card. It's frustrating but guess we'll have to do our own investigative work and trial n error to resolve the problem. Microsoft sucks. ;)

5/25/2021

Mine stuck at 20% for almost an hour.

As I began to go to my Control Panel, it changed from 20% to 73%.  After a few minutes it changed to 74% and has been stuck there for quite sometime.

It appears more and more of Microsoft's updates are failing to install; not sure what's going on.  One would think they'd make sure these will install easily and fluidly ... Shame on you Microsoft!