On 7 February 2014, Mt. Gox halted all bitcoin withdrawals.The company said it was pausing withdrawal requests “to obtain a clear technical view of the currency processes”. The company issued a press release on February 10, 2014, stating that the issue was due to transaction malleability: “A bug in the bitcoin software makes it possible for someone to use the bitcoin network to alter transaction details to make it seem like a sending of bitcoins to a bitcoin wallet did not occur when in fact it did occur. Since the transaction appears as if it has not proceeded correctly, the bitcoins may be resent. Mt Gox is working with the bitcoin core development team and others to mitigate this issue.”
On 17 February 2014, with all Mt. Gox withdrawals still halted and competing exchanges back in full operation, the company published another press release indicating the steps it claimed it was taking to address security issues. In an email interview with the Wall Street Journal, CEO Mark Karpelès refused to comment on increasing concerns among customers about the financial status of the exchange, did not give a definite date on which withdrawals would be resumed, and wrote that the exchange would impose “new daily and monthly limits” on withdrawals if and when they were resumed. A poll of 3,000 Mt. Gox customers by CoinDesk indicated that 68% of polled customers were still awaiting funds from Mt. Gox. The median waiting time was between one and three months, and 21% of poll respondents had been waiting for three months or more.
On 20 February 2014, with all withdrawals still halted, Mt. Gox issued yet another statement, not giving any date for the resumption of withdrawals. A protest by two bitcoin enthusiasts outside the building that houses the Mt. Gox headquarters in Tokyo continued. Citing “security concerns”, Mt. Gox moved its offices to a different location in Shibuya. Bitcoin prices quoted by Mt. Gox dropped to below 20% of the prices on other exchanges, reflecting the market’s estimate of the unlikelihood of Mt. Gox paying its customers.
On 23 February 2014, Mt. Gox CEO Mark Karpelès resigned from the board of the Bitcoin Foundation. The same day, all posts on its Twitter account were removed.
On 24 February 2014, Mt. Gox suspended all trading, and hours later its website went offline, returning a blank page. A leaked alleged internal crisis management document claimed that the company was insolvent, after having lost 744,408 bitcoins in a theft which went undetected for years.
Six other major bitcoin exchanges released a joint statement distancing themselves from Mt. Gox, shortly before Mt. Gox’s website went offline.
On 25 February 2014, Mt. Gox reported on its website that a “decision was taken to close all transactions for the time being”, citing “recent news reports and the potential repercussions on Mt Gox’s operations”. Chief executive Mark Karpelès told Reuters that Mt. Gox was “at a turning point”.
From 1 February 2014 until the end of March, during the period of Mt. Gox problems, the value of bitcoin declined by 36%.
The United States Department of Justice identified Alexander Vinnik, owner of the BTC-E bitcoin exchange, as an alleged key figure in the laundering of Mt. Gox’s stolen bitcoins.