Windows 10 refuses to update - solution found

Run system file checker and see if there are corrupted windows files?

error code 0x80240034.

Windows Update Error Fix https://support.microsoft.com/help/10164/fix-windows-update-errors

Run it?

Also you can check Windows 10 files - https://support.microsoft.com/en-us/help/929833/use-the-system-file-checker-tool-to-repair-missing-or-corrupted-system

P.S. Yesterday they rolled out new feature update - 1909 btw

Upd:
Had huge issues after upgrading from Win 8. So in my case clean install helped a lot - didn't have any issues for a long time.

You can update manually from the site.

As previously mentioned, try to download the file directly and install it. Without a KB number I can't tell exactly what update it is, but it might be this. Download the version appropriate for your system. If you can find a KB number from the description of the update, search for that and download it.

If you have no luck with that, you can always manually reset your Windows Update settings, or use the script provided on that site if you are not comfortable with the command line. You will lose all Windows update log history and so the next time you try to update it will have to go through every single update ever issued and check it against your system to see if it is already installed correctly. Don't be alarmed when it takes a long time.

Try using the Windows 10 Update Assistant. This will often times work when the normal method fails. If you use it, let me know if it worked for you.

https://support.microsoft.com/en-us/help/3159635/windows-10-update-assistant

Go to Your Computer,

Right Click on the drive that Windows is installed on (typically C:)
Click on Properties
Click "Disk Cleanup" button
Click "Clean Up System Files"
Check every box, click OK
Accept prompt asking 'Delete these files?'

Once finished, reboot PC and try to perform updates again.

Good luck!

My PC had a pain of a time getting 1903 at first because some of my device drivers weren't "supported" at the time. If you haven't updated stuff like chipset or video drivers in a while, that might help?

Definitely try Update Assistant. It's a lot more reliable than WIndows Update.

If you want to believe this or not, I started my update download in August. Stuck at 23% downloaded even after multiple reboots. What finally got it going what kind of odd. Few days ago I got prompted to update my NOX player (android emulator)and I saw it had some kind of anti virus software called Segurazo piggybacked onto it. Was a pain to get rid of, but after I did and rebooted the update finally finished an I am now up to date with all of it. Check to see if your anti virus or firewall might be blocking it. Or maybe if any other programs might be blocking it.

I've had this trouble on a number of machines in my office, fairly consistently going back to update 1803. I'm agreeing with several others above. Once this process of fail and try again starts, the only reliable way I've found to push the updates is to install from the Update Assistant. Cleanest still is to use the Media Creation Tool and to make a Win10 thumb drive and install from that.

With 1903, even more than the other Feature Updates, the best option if you have time and patience is to back up your drive, make sure you have the proper disks/codes to re-install your software, and do a clean install from the USB drive. (I rarely have the time and patience to do that, but if I did, I would.)

At the moment I'm delaying updates and hotfixes for 1903, it looks like they create more issues than they solve.

easier solution: Linux

Micro$oft Updates? nah use Antivirus + Win7 prob solved :)