Bitcoin Forum

I have a wallet.dat file with hundreds of coins on it from version 0.3.21
I can't get it to work with the newest version of bitcoinQT. I can't even read it to extract the private keys manually.

I know the coins are still there from checking the public keys on blockchain.info.  any ideas?

install that very old version of the wallet again.and transfer those coins into new address. or try to take linux help because these types of problems generally occurs into window.

Please don't post when you don't know what you are talking about.

The old versions of Bitcoin-qt are no longer available. This is not a problem limited to any OS because the wallet format has changed.

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Op, try starting Bitcoin Core with the -upgradewallet option. See http://www.achow101.com/2016/07/Bitcoin-Core-Troubleshooting#option-startup for help on that.

If for some reason -upgradewallet doesn't work, the source for the older versions is available.  Likewise, pywallet is an option to extract the keys if needed.

E.g. these are links to the pages where various versions are available:
https://github.com/bitcoin/bitcoin/tags?after=v0.3.23
https://github.com/bitcoin/bitcoin/tags?after=v0.5.0rc3

so you could download, compile, then send to a new address.  Or go version 0.3.x to 0.4.x (which, iirc is where the format changed).

Whatever you do at this point, make a few backup copies of your wallet.dat just to be safe.

You need an Hex reader to extract the private keys manually.

I tried the upgradewallet command and got this result:

"upgradewallet" is no longer listed in the available commands when I type "help".

I tried the importwallet command and got this response:


I looked in the wiki to see if there is any difference between the bitcoind command line version and the version with the GUI (bitcoin-qt), but was told they are exactly the same with the same available commands.

This is so frustrating. I thought the hardest part would be not losing the wallet file and not letting anyone else have access to it, but it turns out that even though I did that, there is no backwards compatibility.

And no, I can't run the old version and send the coins to a new address because the version is so old that it no longer has the ability to communicate with the network, so the blockchain can't update.

There is something seriously wrong with Bitcoin when a typical user needs to be able to decrypt a hexidecimal file just to gain access to his coins. Does anybody seriously think that the public will adopt this with all the dangers? Oh yeah, and I lost $7500 in Bitfinex too.  

Are you sure you are running the newest version?  The newest version is called "Bitcoin Core", not "Bitcoin Qt".

There are tools (pywallet) for extracting the private keys from wallet.dat files, but if you still have the old version of Bitcoin Qt that is compatible with that wallet.dat, then you can run that version and extract the private keys with it.

It's not an RPC command, it's a command-line argument. Run Bitcoin Core by entering "bitcoin-qt -upgradewallet" at a command prompt.

It is not an rpc command but rather a startup option.

See http://www.achow101.com/2016/07/Bitcoin-Core-Troubleshooting#option-startup for help on how to start Bitcoin Core with startup options. Use the -upgradewallet option instead of whatever example I wrote in that link.

To access Bitcoins in an old format wallet.dat file simply download and install version 0.7.0 of Bitcoin core using either of these links.

http://eligius.st/~luke-jr/programs/bitcoin/files/bitcoin-qt/0.7.0/bitcoin-0.7.0-win32-setup.exe

http://eligius.st/~luke-jr/programs/bitcoin/files/bitcoin-qt/0.7.0/bitcoin-0.7.0-win32.zip

They are so old they won't sync with the network, but it doesn't matter. Eligius is a well known respectable pool so those files should be safe, but if you want to be sure check them with a virustotal scan.

Here's the results of one I did on the zip file linked to above.

https://www.virustotal.com/en/file/0030a716a84884941dbda8e70846baa8d8aacbe326fe5996b22b555803b5ee1b/analysis/1471172247/

Out of 55 scanners only one reported anything, and that was Sophos reporting it as a potentially unwanted application, not a virus. It said it's Bitcoin Miner (PUA).

First backup your really old wallet.dat file and use a copy of it for this procedure.

Double click the bitcoin-qt-exe after you installed the wallet to get it to create a data folder in appdata, then close the wallet.

Click the Windows Start button then put the cursor in the search box, or go to the Windows 8 Search charm, type %appdata% , and open the Roaming folder shown in the search results.

Then open the Bitcoin folder inside the Roaming folder. Replace the wallet.dat file in there with a copy of your old format wallet.dat, then start the wallet again by double clicking the bitcoin-qt-exe.

When the wallet has started click the receive coins button, then right click each address listed, copy the address and paste it into notepad.

Next click help. then debug window, then click the console tab.

For each address you saved in notepad write the line below into the bottom of the console window (replacing youraddress with one of your addresses from notepad), and press the enter button .

dumpprivkey youraddress

Each time you do that a private key for a Bitcoin address should show in the console window.

Copy the private key for each Bitcoin address, then import them into the latest Electrum, or the wallet of your choice.

There are instructions explaining how to import a private key from a Bitcoin core wallet into Electrum here.

http://docs.electrum.org/en/latest/faq.html#can-i-import-private-keys-from-other-bitcoin-clients



After that you can send your Bitcoins wherever you want.

If you need any help then pm me.

I tested the instructions above with a wallet.dat generated by version 0.1.0 (the first version ever released), and successfully extracted the private key from it using version 0.7.0.