Q: No video, nor audio playback

Hi parakiter,

I understand that you're unable to playback iTunes audio and video content as well as Youtube videos on your MacBook Pro. I know these are important functions to have working, and I'd be glad to provide some tips to help.

Before you begin, I'd recommend that you create a backup of your data using the instructions outlined here:

Use Time Machine to back up or restore your Mac - Apple Support

As a first step, I'd recommend resetting your Mac's NVRAM. This website gives an overview of how to perform this process:

How to Reset NVRAM on your Mac - Apple Support

If the issue persists after you've reset NVRAM, try creating a test user account to help isolate the issue to a system-wide or user-specific problem. This website gives an overview of the process:

How to test an issue in another user account on your Mac - Apple Support

In the test user account, open System Preferences > Sound and make sure "Play feedback when volume is changed" is enabled. This will allow you to easily test for any audio issues by adjusting your volume using the volume keys on your keyboard.

Take care!