Hello guys,

I will sum up everything about our withdrawals (and deposits) system to answer questions:

First we tend to keep low reserves on hot wallets, which is why in times of "uncertainties" with a lot of withdrawals like these days, your withdrawal can go back into "Pending approval" state after being approved, until we replenish the hot wallet (up to 12 hours). Paranoia is our policy (for those who remember when we left MtGox in June last year )
Secondly, and this is what happened here, sometimes a bitcoin withdrawal will fail to be accepted on the network. It happens rarely but does happen. In this case the system will still assume the withdrawal is completed, and you have to contact us by email to support@bitfinex.com so that *a human* verifies if the withdrawal has actually failed, in which case it will be sent again.

For the deposits failing, we made a few adjustment today as sometimes when a lot of transactions occurred we would missed a deposit.

Since I'm on the topic, we do not track withdrawals by TXID so the "falsely failed" withdrawal exploit can not be used against us. Furthermore, we do reconciliate our assets and liabilities every hour in order to quickly spot if a "leak" of crypto-currencies would be happening for whatever reasons. This is something obvious to do for an exchange and I didn't think I would need to mention it, but I think I have to point it out considering recent events.

Finally, if you have an issue on your account, it is better to send us an email at support@bitfinex.com, this will be treated quicker than in this thread.

Thanks for your renewed trust and helping us being one of the top bitcoin exchanges in term of volumes.

Thank you and have a good day
Raphael
Bitfinex team