How do I cancel my blockchain transaction (still unconfirmed)?

27

8

I am using blockchain.info.

I have made a bitcoin transaction of 22.00883562 BTC to the address 1A9eUAc78tGx65X3CuC9WfSKXXgxjU8ccC.

You can see the transaction at https://blockchain.info/tx/97c1af82111cdcf17f878eb6df20c17c59c1b1fc04e8cdce36b8ac6c6d1c969a

I have paid a 0.001 fee but it has been almost 30 hours and it still shows "Unconfirmed".

What could be the error? Also, more importantly, how do I cancel the unconfirmed transaction and get back my coins?

Umle

Posted 2014-03-05T12:51:38.497

Reputation: 271

It seems like your transaction has been confirmed now.Greg Hewgill 2014-03-06T00:31:30.287

2@GregHewgill, that's irrelevant. The question was how does one cancel an unconfirmed blockchain transaction.Pacerier 2014-03-07T05:15:20.417

Well, that answers the "What could be the error?" question - there was no error.Greg Hewgill 2014-03-07T08:26:32.353

2@GregHewgill, considering that he paid 0.001 (10x more the norm) fee, staying "Unconfirmed" for 30 hours is extremely weird and I would say there's a high chance that there's an error with blockchain.info.Pacerier 2014-03-09T16:21:30.280

1

Possible duplicate of Is it possible to cancel an unconfirmed transaction?

Elias Zamaria 2016-12-03T00:53:14.200

22 BTC man... you're rich!Tom Roggero 2018-01-05T20:24:19.510

Answers

12

Cancelling unconfirmed transactions is easy. Just submit a higher fee double-spend transaction. For example: if you send a 0-fee transaction it could take a day before 1 block mines it. Then you send another transaction with the same inputs that just sends the money back to yourself. On this transaction you put a higher fee. This becomes more likely to be mined and will get included in the blockchain - invalidating the slower-to-confirm original.

Erik Aronesty

Posted 2014-03-05T12:51:38.497

Reputation: 367

2How do you double spend if you are sending from a wallet and now no longer have that same amount? IE I've sent from an XRP wallet to Changelly to convert it to BTC over at Coinbase. Now I don't have enough XRP to send.Leon Gaban 2017-05-26T21:42:47.723

This. In theory looks nice, in practice but reallyPedroD 2017-06-06T08:37:08.777

@LeonGaban: I believe that in that case, you're screwed. Anybody knows a workaround?PPC 2017-06-23T11:30:52.030

1

You cannot cancel an unconfirmed transaction. When a transaction has been transmitted to the chain, it's unstoppable. Luckily everything went well for you I see, and it was probably an error on blockchain.info, as pointed out in the comments.

Mathias711

Posted 2014-03-05T12:51:38.497

Reputation: 1 390

8You can cancel an unconfirmed transaction - by double spend this input, therefore original tx will be canceled. Moreover, even if transaction is included in block, it can be canceled - all you need to do is to mine two consecutive blocks without this tx. Therefore, the first block will be orphaned, and all the transaction it has will be unvalidated. This is the very reason we should wait for 6 confirmations.Maciej Mączko 2014-04-24T19:33:40.000

Ahh, I didnt know that. But isnt it quite easy to cancel your BTC transaction in the supermarket (when its implemented), a few seconds after your transaction? That would be a huge disadvantageMathias711 2014-04-24T19:40:08.320

I didn't say it is easy, only that it is possible. I think we can pull this on our own. All we need to do is to buy cheap VPS across the globe (digital ocean?), and using ssh - double spend our coins to our address as soon as we initialize transacion in the supermarket. This is double spending. Note that the bigest BTC processor, Bitpay, does accept 0/unconfirmed txs, because they understand the risk and pay for double spends from their own pocket.Maciej Mączko 2014-04-24T19:57:37.200

Cancelling unconfirmed transactions is easy. Just submit a higher fee double-spend transaction.Erik Aronesty 2016-01-15T18:34:01.960

@Maciej Mączko : I like "mine two consecutive blocks". So easy! Would you please lend me your (super)computer for a day, so that I mine a few blocks, just for sport? :)PPC 2017-06-23T11:26:43.417

1@PPC Thanks for your comment. As I said three years ago, it isn't easy, it is (was) possible. Back then, strong ASIC would give you two consecutive blocks once in a month.Maciej Mączko 2017-06-24T21:06:59.500