No software is perfect. With the introduction of Windows 10 things got worse for Microsoft. Ever since the inception of Windows 10, things don’t work as expected and that eventually prove to be a nightmare for the end user. Here in this article, we will cover one of the most encountered issues with the latest Windows 10 cumulative update┬áKB4338819.

[KB4338819] fails to install with error code 0xc000021a

Although there is still no workaround available to the problem, you can try a few things to see if that actually solve the problem. There are two ways to address the issue.

  • Try to disable Windows 10 automatic update and then try to install the update manually from the link.(for x86 | for x64)Disabling Windows 10 update itself requires a bit knowledge. The process is easy though. Just type Computer Management in the Windows search and click on it. Go to Service and Application and then double click on services. Look for Windows Update in the list programs. Right-click on Windows Update and go to Properties. Disable the Startup Type and then click on stop.Tip: Don’t forget to enable that the Startup type after you successfully install the update as Windows updates are important. It keeps you safe from the various security threats.
  • The other way does not need you to disable the Startup. What you need is two additional KB update. Download these updates and install them sequentially:
    (1) Latest Servicing Stack
    (2) Latest CU

After installing those two you can now check for updates and then install. The issue might get resolved.

Bonus: We have earlier published some of the most common issues and their fixes which you can check out right here by clicking in this link.