user52865: recently I found a very old wallet.dat file back from 2011 (I did some mining back then). I was able to run pywallet to export the keys into JSON file, this file includes private keys and all, so i assume it was not encrypted. The structure is as follows, there are bunch of these.
    {
        "addr": "", 
        "compressed": false, 
        "hexsec": "", 
        "private": "", 
        "pubkey": "", 
        "reserve": 1, 
        "sec": "", 
        "secret": ""
    }, 

The question is - what do I do with this now? I want to check if there any coins that I have mined but i have no idea what the next step is.
I have tried copying the value of "private" into Bitcoin Core's console with "importprivkey" but i get "Invalid private key encoding (code -5)"
Thanks for your help!

user52867: You don't need to import the keys to see if they have a balance or not. Just copy the content of "addr" and use a Bitcoin blockchain explorer such as https://blockchain.info/ to check if there is any BTC on the address.
And i guess you could just import the wallet.dat on Bitcoin Core directly if there is any BTC on any of your addresses.

52865: <p>recently I found a very old wallet.dat file back from 2011 (I did some mining back then). I was able to run pywallet to export the keys into JSON file, this file includes private keys and all, so i assume it was not encrypted. The structure is as follows, there are bunch of these.</p>

<pre><code>    {
        "addr": "", 
        "compressed": false, 
        "hexsec": "", 
        "private": "", 
        "pubkey": "", 
        "reserve": 1, 
        "sec": "", 
        "secret": ""
    }, 
</code></pre>

<p>The question is - what do I do with this now? I want to check if there any coins that I have mined but i have no idea what the next step is.</p>

<p>I have tried copying the value of "private" into Bitcoin Core's console with "importprivkey" but i get "Invalid private key encoding (code -5)"</p>

<p>Thanks for your help!</p>
 52867: <p>You don't need to import the keys to see if they have a balance or not. Just copy the content of "addr" and use a Bitcoin blockchain explorer such as <a href="https://blockchain.info/" rel="nofollow noreferrer">https://blockchain.info/</a> to check if there is any BTC on the address.</p>

<p>And i guess you could just import the wallet.dat on Bitcoin Core directly if there is any BTC on any of your addresses.</p>
