You guys really need to learn your Bitcoin history! Bitcoin had been rolledback!

8th August 2010 - 92 billion BTC into existence

On 8th August 2010 bitcoin developer Jeff Garzik wrote what could be mildly described as the biggest understatement since Apollo 13 told Houston: “We’ve had a problem here.”. “The ‘value out’ in this block is quite strange,” he wrote on bitcointalk.org, referring to a block that had somehow contained 92 billion BTC, which is precisely 91,979,000,000 more bitcoin than is ever supposed to exist. CVE-2010-5139 (CVE meaning ‘common vulnerability and exposures’) was frighteningly simple and exploited to the point of farce by an unknown attacker. In technical language, the bug is known as a number overflow error.So instead of the system counting up 98, 99, 100, 101, for example, it broke at 99 and went to zero (or -100) instead of 100. In layman’s terms, someone found a way to flood the code and create a ridiculously large amount of bitcoin in the process.

The fix was the bitcoin equivalent of dying in a video game and restarting from the last save point. The community simply hit ‘undo’, jumping back to the point in the blockchain before the hack occurred and starting anew from there; all of the transactions made after the bug was exploited – but before the fix was implemented – were effectively cancelled.

How serious was it? Bitcoin’s lead developer Wladimir Van Der Laan is pretty blunt about it, telling me: “It was the worst problem ever.”

Source1: http://www.coindesk.com/9-biggest-screwups-bitcoin-history/
Source2: https://bitcointalk.org/index.php?topic=822.0