HowTo run NodeCore

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See: Main_Page, NodeCore_QuickStart, NodeCore_Operations,, TestNet


NodeCore is the service that runs the VBK blockchain. It is written in Java, and runs on Windows, Linux, and Mac.

To see an operations guide for installing NodeCore, see: NodeCore_Operations

To see a quickstart to get NC running fast, see: NodeCore_QuickStart

To modify the file, see:


Unzip the package:

Windows Mac and Linux
Unzip the nodecore-*.zip file In the bin folder, then run nodecore.bat Unzip to your preferred directory, then run nodecore.

Note: On Linux & Mac systems, you may need to make the nodecore shell script executable by running the following command:

When you first run NodeCore, it will create several other files in a new mainnet folder (, veriblock.nodecore.log, nodecore.dat, etc...), and load the existing blockchain.

NodeCore may take several minutes to load all the blocks in the blockchain. See the highest block at This shows the number of blocks your local instance must load to be in sync with the chain. NodeCore will create a cache file such that when you restart it they will load faster next time.


What startup flags are available

-d, description: The data directory where NodeCore generated files reside
-c, description: The configuration file location

How to set NodeCore Log Path

You can specify log path with an environmental variable "NODECORE_LOG_PATH".

Example for linux:

export NODECORE_LOG_PATH=/home/user/nodecore_logs/

How can block times be negative?

A negative age indicates the miner's clock was ahead.

For more background, see:

How to upgrade NodeCore and keep your wallet

Since mainnet is now live, updating is very fast.

If you do NOT have a previous wallet/address/balance download the latest nodecore found here

If you do have a wallet/address/balance that you want to carry over make sure you do the following:

  1. Make sure you have a backup of your wallet! You can copy the mainnet folder which contains your wallet.dat, or use the NodeCore_CommandLine#importwallet command from the NC_CLI.
  2. Ensure that you unzip your newlyl downloaded NodeCore to a new folder location - do not overwrite your previous version
  3. In the new version:
    1. Create a mainnet folder most likely in the "nodecore-0.X.X/bin" directory.
    2. Copy in your previous wallet.dat and walletconfig.dat files into the "nodecore-0.X.X/bin/mainnet" directory.
  4. Run your new version of nodecore and start to sync.
  5. When you run NC_CLI getinfo on the new version of the running nodecore, you should see your previous wallet and balance.

How to upgrade NodeCore PoW and keep your Bitcoin wallet

When upgrading your PoP miner, you can copy the file "bitcoin-pop.wallet" from the bin folder of your current PoP miner directory to the bin folder of your new PoP miner.

How to specify a data directory for NodeCore

NodeCore can take a data directory -d as part of the startup.

Example for Linux:

cd /<myDir>/nodecore-0.4.10/bin
./nodecore -d /home/user/data/
  1. will be in /home/user/data/
  2. /mainnet folder will be in /home/user/data/mainnet

Example for Windows

cd <myDir>\nodecore-0.4.10\bin
nodecore.bat -d C:\data

# will be in C:\data\
# /mainnet folder will be in C:\data\mainnet

How to send from a specific address?

send <amount> <destinationAddress> [sourceAddress]

How to set NodeCore log level

Currently NodeCore log level can be set through the NODECORE_LOG_LEVEL process environmental variable. Once set, NodeCore needs to be restarted.

The default is "INFO", which can create very large log files.

This impacts the "veriblock.nodecore.*.log" (which is the biggest log file). It does not affect the other, much smaller, log files.


This is an example of setting it in Windows, and then starting NodeCore:



Run in same session, such as a screen:



NodeCore is stuck on a block

Ideally this should not happen, but if it does first try restarting NodeCore.

Java out-of-memory

It is possible that you only have a 32-bit version of Java installed. 64-bit is highly recommended.

Modify the start file (nodecore.bat for windows, nodecore for linux) to increase the memory limit. Pass in a value, such as "1024 MB" into the DEFAULT_JVM_OPTS variable:


NodeCore keeps turning off with "Application exit"

If messages like:

INFO [main] n.Program [] Application exit

Then something external is shutting off NodeCore (such as a server restart, external process kill, or something else).

Having trouble on a mac

On a Mac, you need to install OpenJDK, our releases are tested on the LTS versions here ->