I have advanced in my research. The UTC/JSON file in question is a 491 byte file.

There are 256 random characters in the file with each 16 possible characters. Like a 256-number long padlock with each 16 possible numbers.

Even if I learned how to write a script that creates a UTC/JSON file for each possible combination, there would be 16^256 possible files, which amounts to 16^256*491 bytes or roughly 8.418*10^308 GIGABYTES. You read that well.

Considering this, my only chance resides in retrieving the actual file through file recovery programs.


At this point I am desperate and I need your help. I am quite new to ETH, I got very interested and I started mining two weeks ago with my personal computer and, seeing potential in the currency, I bought 1.0 ETH a few days ago. I will give a 0.1 ETH reward if someone has a solution for me.

Short version:

UTC file was mistakenly deleted, I was able to recover it, but now Mist, Ethereum Wallet, geth and MyEtherWallet don't recognise the file as a valid wallet file. Might be corrupted after recovery.

Long version:

Yesterday I was running geth to update the blockchain. I wanted to access the %APPDATA%\Roaming\Ethereum folder to see the actual size of the blockchain.

But Windows gave me an error saying that the folder was not in this location.

I found that strange, restarted my computer, nothing changed. I figured the folder got corrupted, so I carefully noted my ETH address and deleted the "%APPDATA%\Roaming\Ethereum" folder to download the whole blockchain again.

I did NOT know that the UTC-2017-xx-xx-xxxxx file was my actual wallet and did NOT back it up.

I thought with the address and the password I would be in the clear.

Then I wondered why my wallet didn't show up on Mist, so I looked it up and realized I deleted my UTC/json file which was in the "%APPDATA%\Roaming\Ethereum\keystore" folder.

I downloaded a few file recovery programs, ran them and got my UTC/json file back. Recuva said it was not overwritten and that its quality was "Excellent".

So I sighed in relief and put the file back in the new "%APPDATA%\Roaming\Ethereum" folder.

I opened Mist: nothing. I opened Ethereum Wallet: it showed up!... and disappeared a second after. I opened geth and ran "geth account list" and it did not show up.

It made me depressed at this point. Then I saw someone on a forum suggest MyEtherWallet for a different problem but I figured it could work.

So I dropped the file and it said "File selected UTC....... is not a valid file".

So now I'm screwed, big time. I don't know what else to do. I will take any of your suggestions.

For now I saw that the UTC/json file weighs 491 bytes. It's not heavy. Could I specifically manipulate it and "bruteforce" it into a valid wallet file with trial-and-error?

Thank you for your time.

  • Hi Eric, I haven't sent you anything. I hope you understand I am reluctant to sending you the UTC file along with its password, just in the event that you can actually do something to recover the wallet, you could do whatever you wanted with it, such as transferring the funds somewhere else. If you do want to help, which I hope you do, please do it here or send me a message.
    – BuckField
    Commented Jun 16, 2017 at 17:41
  • 3
    Just to jump in here... Under no circumstances send your UTC file and password to anyone, ever, unless you're absolutely certain you can trust them. The Stack Exchange reputation system can be gamed as easily as any other reputation system, users can be impersonated, and seemingly trusted users could turn out to be crooks. Especially in the world of cryptocurrency. Even if you trust a person not to run off with your wallet, you have to trust that they'll protect the information as if it were their own. You're effectively doubling the size of the attack surface by distributing your data... Commented Jun 16, 2017 at 18:12
  • 1
    If mist says it is not a valid then it is likely nor a valid wallet file. A valid file has something like "version":3,"id":"xxxxxxxx-xxxx-xxxx-xxxxxxxxxxxx","address"."xxxxxxxxxxxx". Where xx are replaced by hexadecimal digits, ie 0-9,a-f. Perhaps your recovery utility got the name wrong, check for the other files. To help filter the file should be less tha 1Kbyte in size.
    – Ismael
    Commented Jun 16, 2017 at 18:12
  • Comments are not for extended discussion; this conversation has been moved to chat.
    – eth
    Commented Jun 18, 2017 at 10:26

1 Answer 1


All you need to do is import the JSON file using mist. Open mist, press Ctrl I and drop your wallet json file into the resulting dialog.

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  • Hello 0xcaff, thank you for your answer. It did not work, however. I believe the JSON file is actually corrupted. I tried with a new account and it did work. It is thus the specific JSON file where my funds are that has a problem. It answered with "File not recognised". But thank you for trying. I'm running out of ideas.
    – BuckField
    Commented Jun 16, 2017 at 18:00
  • Don't use your hard drive for anything, image it using a live CD. Then use grep in binary mode to search for json strings in the image like {" or "iv":. You should find your wallet or a fragment of it. Repeat until you have your entire wallet.
    – 0xcaff
    Commented Jun 16, 2017 at 20:09

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