Bitcoin Forum

Hello & thanks for reading,

To clarify one thing from the start, despite this is a new bitcointalk.org account I am not new to the community, nor I am a complete noob. I've just been inactive a very long time and therefore my old user account is blocked.
See here if you are interested further, or can help me with this topic: https://bitcointalk.org/index.php?topic=2527012.msg25801490#msg25801490

To the more relevant topic:
I could now tell you how stupid I am with accidently formatting one of my main harddrives with the command "dd if=/dev/zero of=/dev/sdb" and of course, yes you guess it, a bitcoinwallet with let's say a decent amount of coins saved on it.
But instead I will just tell you that the backup I had of one of my bitcoincore: "wallet.dat" files (yes it's the one from above...) is corrupted and now I ask for help.

I have absolutely no Idea if this wallet is recoverable at all, or if it is even worth the try.
The private key is encrypted with a very strong password, so I would have no problem in handing the file over to potential helpers.

Edit: Due to hint of some members I reduced the reward to a more reasonable value.
I offer 0,1 BTC to the first one who comes back to me with a readable (and of course spendable) copy of the wallet. Or just extract the private key in a read-/spendable form.
As this is about a great sum of money I would need someone to Escrow this, as I am not up2date regarding this, I am open for suggestions on the "who and how", about the Escrow part.

Again thanks for reading and hoping for useful input :)

You might want to take a look at pywallet too. You need to install Python first (unless you're a Linux user where it's most likely already there).

Make a bunch of copies to different media first just to be sure and play around with pywallet.

I suggest you exhaust all your own options first before handing your wallet over to someone else.

I vote for pywallet too, if bitcoin-qt fails to salvage.
This thread may be useful for you (https://bitcointalk.org/index.php?topic=1404609.msg14257235#msg14257235)

I see you like being thorough :o

Let's start from here: how did your backup get corrupted? I often read this, but in general digital files don't just get corrupted out of the blue. Something must have happened to it. "Corrupted" can be a lot of things.
What version of Bitcoin Core were you using when you last used the wallet.dat before you made the backup?

Are you sure you didn't make another copy you've forgotten again? It's a long shot, but you wouldn't be the first!

As far as I know, https://walletrecoveryservices.com/ can be trusted. He's specialized in password recovery, but he might have some tricks for corrupted wallets too. I suggest you send him a message.

It's always worth trying, you have nothing to lose, and at least an experience to gain.

One way or another, this requires your password. Be very careful to whom you send both wallet and password.

I'm a bit surprised with the number of people offering rewards to rescue their coins lately. In general, people are willing to help without rewards, but you are of course free to offer rewards.
I'd say OgNasty (https://bitcointalk.org/index.php?topic=303281.0) is trusted. It'll cost you 1% of the escrowed amount as a fee. I just don't think a $12000 reward will get you any better answers than a $1000 reward.

Actually, in my experience on this forum, larger rewards tend to result in worse answers.

Knowledgeable people that are here to help are willing to help simply for the sake of being helpful.  You're welcome to voluntarily send them something to show your appreciation afterwards, but never required to.

On the other hand, when you offer money (or anything of value) then dozens of people that know almost nothing about your problem will run a google search and copy-paste the first thing they see. They'll just repeat stuff they've seen in other posts without any understanding of what they are saying or if it applies. They have no idea if they are being helpful or not, and are quite likely to be wasting your time, but they don't care.  If they get lucky and stumble across useful information they get free money, and if they don't then it doesn't cost them anything (but does cost you a lot of time and effort).  Frequently their advice can result in making your situation worse.

Furthermore, when you offer a large reward, it makes it clear to the scammers and thieves that you are feeling a bit desperate.  They will see that as an opportunity to try and take advantage of you.

I was just watching the "https://walletrecoveryservices.com/contact/" site again and saw you post.
i have seen his work he is trusted.
you can surely contact him and he will do the work.
at least he got some reputation .

Thanks for all of your input. I already tried --salvage and pywallet, both without success.


Since the backup is on an external drive, I guess that I maybe once removed the drive to soon (without safe removal). About the version, I am not sure, but a rather old one, as this happened back in 2014 / 2015. Until recently I did not check my backup...

Seems like that's my best bet. I will try that.
Thanks for your help!  :D

if u have already tried those you can try this alternative way, yuo can try with HEX editor a good guide is here, is faster link the guide so


here

https://bitcointalk.org/index.php?topic=2012533.msg20054695#msg20054695

Pretty sure this won't work on a encrypted wallet, correct me if i'm wrong.

This makes me think your harddrive is "cluster f*cked".

A file can be corrupt in two ways:

1 - The software (in your case bitcoin core) had a failure when writing the file
2 - Your harddrive failed and corrupted the file

In case 1 you can ask for extern help -> copy the file, hand it over and let somebody try to recover it
In case 2 you can NOT ask for extern help by handing out a copy of the file since you can not hand over the harddrive index and cluster build.

In case 2 (i am 90% sure this is your case) the only thing you can do is hand over the complete harddrive to a specialist who will try to rebuild or restore your harddrive index and clusters with special software.

If i where you i would look for a local company that can rebuild broken harddrives and ask them if they can recover the file, most of those companies do a quick scan and tell if it's possible or not within 1 hour.

OP can at least check if his wallet.dat encryption key is intact.
Following the steps here: https://walletrecoveryservices.com/limited/
If his encrypted_key is larger or less than 48 bytes, well god-bye Mr. wallet.dat.
Maybe Dave has some special methods to recover it though.

Interesting idea, I will try that.

What exactly happened when you tried pywallet? It would be useful to know exactly what you tried, and therefore, what you didn't... just on the off-chance that someone might be able to spot a flaw in your methodology...

"pywallet didn't work" doesn't really tell us much ;)

Sorry to say but you might have to trust an "expert" with the file, and to trust that he.she wouldnt run away with the money. After all, it would be a crime and who would commit a crime for a louse, lets say, 10 BTC, 140K dollars? Not worth the bad karma :)

I indeed believe in the concept of karma, so I would get it back in some way anyhow. But i would prefer to have the coins in this life ;)

Of course you already ran a check-disk with file system error fixing and bad sector scan/repair, right? Are there more files corrupted on that disk?

You are right.  :D

That's what I tried:

python pywallet.py --recover --recov_device=/path/to/wallet/wallet.dat --recov_size=1Mo --recov_outputdir=/home/blabla/

Paths are obviously not the real one's

It scanned the wallet and says nothing found. (yes I entered the correct password)

Hello,
yes I already tried that. It shows no other corruptions and as far as I understand system error fixing and error repair, it would alter the file even further and therefore would make it worse?
But it was worth the try.

Thanks for your input.

Thanks for all of your inputs.
I've just sent the wallet over to these guys.
Hopefully he/they can fix it.