Before you do anything, you probably want to make a couple backups of the wallet.dat. Check that the backups are in order before continuing.
zapwallettxes only works on the start up of Bitcoin Core. First shut down your bitcoin-qt, then open a terminal.
Write:
bitcoin-qt -zapwallettxes=2
If this doesn't start bitcoin-qt, you might need to go to the applications folder. You switch to the installation directory:
cd Applications/Bitcoin-Qt.app/Contents/MacOS/
And then run the application from that folder:
./Bitcoin-Qt -zapwallettxes=2
This should start Bitcoin-Qt, but delete unconfirmed transactions from your wallet. After it loaded completely, check whether the transaction is still listed. The transaction should no longer be listed and your balance should show the full amount. After this you should be able to normally start Bitcoin Core.
If the transaction is still shown, and you're running a very new version of Bitcoin Core, it might have been in your Bitcoin Core's own memory pool i.e. the set of unconfirmed transactions as well.
In that case, you'll need to delete the persisted memory pool.
By default the data directory on Mac is:
~/Library/Application Support/Bitcoin/
In that folder, you should find a mempool.dat. After you shut down and before you restart with zapwallettxes=2, delete the mempool.dat (and no other files).
Bitcoin Core will probably prohibit you from creating new transactions until it is synchronized with the network.
3This isn't a site to look for people to hire. You can ask about how to solve it yourself, but you'll need to give more information. – Nate Eldredge – 2018-01-22T04:57:00.423
I'm not hiring anyone, it is a good gesture for someone's time and help. I have a potential $3M windfall here so trying to get assistance. Do you blame me? What info do i need to add? – merger – 2018-01-22T05:02:21.760
Nothing to do with blame, it's just that Stack Exchange doesn't think that posts offering money are a good idea. See https://meta.stackexchange.com/questions/25615/offering-actual-money-as-a-bounty. I have edited this out for you.
– Nate Eldredge – 2018-01-22T05:12:35.0602You've posted something about a transaction but it's unclear what it's about. Is this an incoming transaction that you want to get confirmed, or an outgoing transaction that you want to cancel? It would really help a lot if you were willing to post the transaction ID. – Nate Eldredge – 2018-01-22T05:13:21.873
You can't offer money for help. – Adam – 2018-01-22T05:13:57.097
This is from a transaction that was sent in 2014 with no transaction fee. It just shows as unconfirmed. When I check the generated txid on Blockchain.info, there is none which means the transaction never happened. The coins are presumably in limbo. I found this out by just downloading Bitcoin Core (qT) and switching the generated empty wallet.dat with the recovered wallet.dat file from 2014. The transactions displayed upon booting up Bitcoin Core. – merger – 2018-01-22T05:29:38.017
I have been reading online for hours that it is possible to retrieve the coins but I am unclear as to how. Do I fully install Bitcoin Core (150GB), then try to cancel the transaction that way so the BTC returns to my wallet balance or where do I go from here? I'm clueless. – merger – 2018-01-22T05:30:17.963
As far as the rest of the world is concerned, that transaction never happened. Your client just doesn't know that. You can use
-zapwallettxesto make your client forget about it. However, you'll have to download the whole blockchain (that's the 150GB) to see your correct balance and be able to spend it. You might also be able to import your wallet into "thin client" software that would let you do this without the full download, but I can't tell you the details as I've never tried this. – Nate Eldredge – 2018-01-22T05:32:55.3872Just extract every address from your wallet and see if any have a non-zero balance. Then, for those, extract the private keys. Look for the
pywallet.pyprogram that will extract addresses and keys from a wallet.dat file. – David Schwartz – 2018-01-22T06:05:19.660David, they are going to show a 0 balance as when I sent the transactions back ages ago, I did not include a tx fee through Multibit. I remember I was trying to buy something and told the guy the funds were sent but they really didn't send as I didn't include a fee. Now the funds are in limbo so I have to -zapwallettxes I guess (not sure how) upon downloading the entire blockchain and then the tx will drop and the BTC will appear in my wallet. (I think?) Someone please help. – merger – 2018-01-22T06:14:53.763
Do you know the private key??? – Crypto – 2018-01-22T05:46:45.177
I have the wallet.dat raw file. I used multibit. No passphrase, etc is associated. At this juncture, I am still lost. I need to download the entire blockchain. Upon doing so, my wallet.dat file (from 2014) is associated with it already. I then need to -zapwallettxes (how do I do this via my Macbook?), then the 200 BTC + 41.20 BTC transactions will drop off and the funds will be present in my balance. I am now a millionaire? Is this what is going to come to fruition? – merger – 2018-01-22T05:48:37.753
If all your addresses have a zero balance, then you don't have any bitcoins. If the send didn't go through, then the bitcoins should still be there. – David Schwartz – 2018-01-22T23:41:47.490