Prevented about Obito? What does that mean?
My apologies, as English isn't my native language I used the wrong word.
What I wanted to say, is that if I were Itachi I would have warned Hiruzen and the elders about Obito. Actually, Anbu Itachi and Obito met each other and Obito even helped Itachi to massacre the clan.
And personnaly, I never understood why Itachi never secretly warned Konoha about Obito, suggesting that he was the one responsible of the Kyuubi attack. My opinion is that it was a plothole, in the FG Itachi wasn't supposed to be an anti hero / double agent.
Some people might answer that if Itachi did that, he would break his own cover toward Obito. But I think it wouldn't necessarily happen if Hiruzen and the elders took this information as top secret by not publicy revealing it, in order to cover their best agent. And they actually would keep it secret, because politically it's better to publicy say that Kyuubi attacked Konoha because of an accident than because someone infiltrated the village and broke every defense system.