Common problems and resolutions

When I try to start the software, I get a Java error.
Nxt relies on Java v1.7 and the latest version of the Java Developer's Kit. Make sure you download and install latest version installed from Oracle!

You can check to see which version of Java is running on your computer by running the following command in a terminal window:

java -version

I cannot load the client in a web browser
Nxt uses a couple of different ports, but each port uses a different protocol. To access your client with an unencrypted connection, use this address: http://localhost:7874/ To access your client with an encrypted connection, use this address: https://localhost:7875/ For port 7874, you MUST use http. For port 7875, you MUST use https.

If neither of these addresses work, you can also try these addresses: http://127.0.0.1:7874/ https://127.0.0.1:7875/

My blockchain won't load!
Your data files may have been corrupted. Try the following steps:


 * Stop your Java software.


 * Navigate to your "nxt" folder and delete all the files ending in ".nxt" (NOT ".nxt.bak"!)


 * Restart your Nxt software, wait a few minutes, and then check the Nxt client to see if the blockchain has begun to load.  If not:
 * Stop your Java software again.
 * Download new blockchain files manually from this location .  Unzip the files and use them to replace the ones in your "nxt" folder.
 * Restart your Nxt software, wait a few minutes, and then check the Nxt client to see if the blockchain has begun to load.  If not:
 * Stop your Java software
 * Delete your "nxt" folder
 * Re-download and re-install the Nxt software

My blockchain files keep getting corrupted
Often, the blockchain files get corrupted as a result of the Nxt software being forcefully terminated (by using Ctrl-C in Windows, by forcibly closing the terminal window, or by using "kill -9" in UNIX). To create a more graceful means of stopping the software, alter your "java" command for starting Nxt to something like the following: java -jar start.jar STOP.PORT= STOP.KEY= where:

When your Nxt software is started in this way, you will be able to exit it gracefully by running the following command: java -jar start.jar STOP.PORT= STOP.KEY= --stop where and are the same values you used when starting the server.
 * is any available TCP port.  Almost any number between 10000 and 65535 should be fine.
 * is any simple password

I'm running MacOS 10.6, and it won't support Java 1.7. Do I have to update MacOS?
No! There is a workaround for installing Java JDK 1.7 on MacOS 10.6. You must be comfortable editing plist files in order to use this workaround.


 * 1) Go to:
 * 2) * /System/Library/CoreServices
 * 3) Edit:
 * 4) * SystemVersion.plist
 * 5) Change: ProductUserVisibleVersion = 10.6.x and ProductVersion = 10.6.x to:
 * 6) * ProductUserVisibleVersion = 10.7.8
 * 7) * ProductVersion = 10.7.8
 * 8) Install JDK 7 and change SystemVersion.plist back to normal
 * 9) Go to and open /Library/Java/JavaVirtualMachines/jdk1.7.0_40.jdk
 * 10) Uncheck both Java 6 VMs. Now Java 7 will load first.

The client says I have 0 NXT in my account but I have not transferred my coins anywhere
This could happen for two reasons:
 * The blockchain has not been completely downloaded in your software yet, and the blocks containing your deposits are yet to be downloaded. Check the time stamp on the latest block in the "Blocks" panel. If it is not very recent (within a minute or two), wait and give the software some time to catch up. If you are impatient, you can download an almost-complete blockchain from this location -- just unzip them into your "nxt" folder.
 * There appears to be a bug in the client software right now that causes balances to be improperly shown. Try stopping and restarting your Java software, and then unlock your account again.

I created an account but I don't see it referenced in the blockchain
In general, you can use the Nxt blockchain explorer to search for your account, examine your balance, transaction history, and more. Information about your account will not appear in the blockchain until there is at least one confirmed transaction that references your account. This is because the blockchain is a record of transactions, not account information.

If you have created an account but have never sent any Nxt to it, the account will not appear in the blockchain.

From here, you may want to learn more about the Nxt client or read our FAQ!