I was recently doing a maintenance window for a customer and had an issue with several of their servers giving me an Error Code 80243004 – Windows Update encountered an unknow error when I was trying to install updates.  After researching, I came across an article with a very simple and weird fix for the issue. 

  1. Right click on the taskbar and select Properties.
  2. Click the Customize… button on the Taskbar and Start Menu Properties window.
  3. On the Notification Area Icons window, make sure Always show all icons and notifications on the taskbar is checked and click OK.

After turning on the notifications for Windows Update, I was able to successfully install all Windows Updates.