Version: 1.6.1-stable
Git Commit: 021c3c281629baf2eae967dc2f0a7532ddfdc1fb
Architecture: amd64
Protocol Versions: [63 62]
Network Id: 1
Go Version: go1.8.1
Operating System: windows

The above is my geth installation, I need to initialize testnet with some default balance for some address - how can I do this? I tried with the genesis.json from https://github.com/ethereum/go-ethereum/wiki/Private-network and initialized the private block chain, created an account, replaced the address in the custom genesis file with that and re-run the init, but it failed with

Fatal: Failed to write genesis block: database already contains an incompatible genesis block (have 15ecff6ddb9d4db4, new 834a88447f2091cc)

How can I add some balance to the address?

2 Answers 2


You can run the command:


In the geth console. This will start mining and add ether to your default account.


Looks like you are trying to set geth private net node on your machine, I posted the steps today in another question. This should help you out, please take a look.

How do I set up a private ethereum network?

Before following the steps, remove the existing datadir and genesis file.

Note - datadir folder has keystore and that has to be deleted to start from scratch

Once you set up private net then you can use eth.SendTransaction({from: accounthash_sender, to: accounthash_reciever, value: the_amount}) to send some balance to other accounts from default account. Your default account would have balance from genesis block instantiation.

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