How to upgrade Windows-10 version, stuck at KB4493440 [duplicate]

As mentioned in my previous question, I can't install a Linux subsystem on my Windows-10 machine, as the version is too old (1709 while at least 1903 is needed).

I thought that I could solve this, using a simple Windows upgrade, but this seems not to work. Why is that? Are there limitations to Windows-10 version upgrades (it's the computer of my employer, not my own)?

First edit:

The last package my computer is trying to install, is the following one (sorry for the Dutch):

2019-04 Cumulatieve update voor op Windows 10 Version 1709
for x64 gebaseerde systemen (KB4493440)

After having tried this (without succeeding), this is the message I see on my Windows update screen:

Er wordt een update voorbereid voor uw apparaat, maar dit is nog niet gereed.
We blijven het proberen, maar u kunt het ook zelf nu opnieuw proberen.

Freely translated:

An update is prepared for your device, but this not ready yet.
We keep trying, but you might try it yourself too.

I'm already seeing this message for several days now.

Edit after some more investigation:

As mentioned on this website, I've stopped the Windows update service, cleaned the datastore directory (%windir%\SoftwareDistribution\DataStore) and restarted Windows update service again, but the problem still appears. (I checked the mentioned directory and the files Datastore.edb and Datastore.jfm have been re-created.)

I also performed a system file check, which mention everything being ok:

sfc /verifyonly
Beginning system scan. This process will take some time.
Beginning verification phase of system scan.
Verification 100% complete.
Windows Resource Protection did not find any integrity violations.

What can I do?

2 Answers

(This answer is a copy ofanother answerof mine, put up here at the request of the poster for the purpose of the bounty. After the bounty period, I plan to mark this post as a duplicate.)

Windows Update is problematic and can fail in many ways.

Below is a list of advice that may help Windows Update work better:

• Run the Windows Update troubleshooter in:
  Settings > Update & Security > Troubleshoot > Additional troubleshooters > Windows Update > Run the troubleshooter

• Run Microsoft's Windows Update Troubleshooter for Windows 10

• Reset Windows Update components by running these commands in an elevated Command Prompt:

  net stop wuauserv
  net stop cryptSvc
  net stop bits
  net stop msiserver
  Ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
  Ren C:\Windows\System32\catroot2 Catroot2.old
  net start msiserver
  net start wuauserv
  net start cryptSvc
  net start bits

  If all goes well, delete the .old folders (or return them if a problem arrives).

• Run the DISM tool in an elevated Command Prompt:

  Dism /Online /Cleanup-Image /ScanHealth
  Dism /Online /Cleanup-Image /CheckHealth
  Dism /Online /Cleanup-Image /RestoreHealth

• Run the following in an elevated PowerShell shell:

  SC config trustedinstaller start=auto

• If nothing fixes the problem, use a heavy gun:
  Repair Install of Windows 10 with an In-place Upgrade

If your problem is that you cannot update Windows 10 to a higher version. I recommend updating manually, following these steps:

• Go to Microsoft support website
• Click the Update Now button to save the tool on your device
• Launch the downloaded tool
• Click the Update Now button

If this doesn't work for you, you should try "media Creation Tool":

• Go to Microsoft support website
• Click the "Download tool Now" button to save the tool on your device
• Launch the downloaded tool
• Select "Upgrade this PC now", next and Install.

You can read more about this topic in Windows central

I hope it helps you.