Windows 10 K&N Edition Anniversary update - Media player update not working

Solution 1:

Media Features Pack (KB3133719 which supercedes KB3099229) for Windows 10 Anniversary Update is right here:

Download Media Feature Pack for N versions of Windows 10 from Official Microsoft Download Center

And the corresponding MS Knowledgebase article is at Media Feature Pack for N editions of Windows 10 Version 1607

Src: Where is Windows Media Player in Windows 10?

Solution 2:

For Windows 10 Creators Update v1703 (Build 15063), you need to install the Update KB4016817

Download:
32Bit
64Bit

This also restores the Game Mode/XBox entry in the settings app, which is new in Creators Update.

For Windows 10 Fall Creators Update v1709 (Build 16299.15), you need to install the Update KB4039813 from Downloadcenter

For Windows 10 April 2018 Update (Version 1803 - Build 17134.x), you need to install the Update KB4057437 from here.