Windows Update can sometimes be a useless tool. Failing to download an update, failing to install an update, corrupting an update (both downloading or installing) or sometimes just not acquiring updates at all. When this happens another easy way to install the updates you need is from the Windows Update Catalog. It is a very useful tool when all else fails. 

Using this website is extremely easy, although it looks as though you are going to be downloading a virus... To use it, you will need the update KB id. In Windows Update it displays it next to the name of the update usually in brackets. 

Windows Malicious Software Removal Tool x64 - v5.113 (KB890830)

This is an example update with the code KB890830. Copy the code or type it manually into the search bar and search. This will show you all results for that update. Be sure to select the correct update for the correct 'Product' / Windows Version you are using. From here it is just like any other program install; click Download and run the installer.