Google has blocked Microsoft's YouTube app for Windows Phone 8 just two days after it landed in the Windows Phone store.

In May, Google wanted Microsoft to remove its redesigned YouTube app for Windows Phone 8 because it didn't include ads. The app also gave users the ability to download videos. Microsoft obliged by pulling the app from its store, and then both companies took the whole summer to collaboratively bake a new app that followed the "rules".

Read: Microsoft re-releases YouTube app for WP8, now with Google's blessing

So the new, new YouTube app for Windows Phone 8 landed in the Windows Phone store this week. The app cancelled the ability to download videos - and there were plenty of advertisements afoot. So, what's the problem? Here's Google-owned YouTube's statement on the matter:

"We're committed to providing users and creators with a great and consistent YouTube experience across devices, and we've been working with Microsoft to build a fully featured YouTube for Windows Phone app, based on HTML5. Unfortunately, Microsoft has not made the browser upgrades necessary to enable a fully-featured YouTube experience, and has instead re-released a YouTube app that violates our Terms of Service."

Read: Google wants Microsoft to remove its redesigned YouTube app for WP8

Engadget - citing unnamed sources - reported that Microsoft didn't want to develop an HTML5-based app. Despite Google's involvement, the company created its own native version and "reverse-engineered the ad system in order to satisfy Google's terms of service." Google therefore couldn't promise the right ads would play, so it decided to block the app once again.

Update: David Howard, vice-president and deputy general counsel at Microsoft, on Monday wrote a scathing blog post titled "The limits of Google’s openness". He said Google blocked the YouTube app because it was not HTML 5-based. That's interesting - because Google's YouTube app for Android and iOS is not HTML 5-based either. Here's an excerpt from Howard:

"We think it’s clear that Google just doesn’t want Windows Phone users to have the same experience as Android and Apple users, and that their objections are nothing other than excuses. Nonetheless, we are committed to giving our users the experience they deserve, and are happy to work with Google to solve any legitimate concerns they may have. In the meantime, we once again request that Google stop blocking our YouTube app."