Adverts that appear at the start - or during - YouTube videos are served from the same location as the actual video content, which means it is not possible to block them through traditional domain/URL lists. In order to prevent adverts from being shown on YouTube you will need to ensure the 'YouTube: Remove Adverts' content modification policy is in place.
Note that this content modification policy requires you have HTTPS Decrypt and Inspect enabled, see our help topic, Managing HTTPS inspection policies.
- Navigate to Guardian > Content Modification > Policy Wizard
- Crate a content modification policy with the following settings
Who: Everyone *
Where: Everywhere *
When: Always *
Action: Apply - YouTube: Remove Adverts
* - Change as required
Once this new content modification policy has been created it will take a few moments to take affect. Once applied you should no longer see video adverts at the start, or during, YouTube videos. Note that other non-video adverts (popups, featured links, etc) must still be blocked by ensuring the 'Adverts' category is in a block policy in your web filter.