Most of the Altcoin core wallets are based on Bitcoin QT wallet. At some point of time you may face synchronization issues with your core wallet. If your wallet is not syncing then there are quite a few ways to troubleshoot and fix it. If none of the troubleshooting methods work then only way to fix your wallet is by deleting all core files and syncing the blockchain from start. Since the wallet uses P2P connection syncing the blockchain from start will take a long time to complete. Fortunately, you can speed up this process by using a file called Bootstrap.
Bootstrap.dat is a flat binary file which contains up to date blockchain data. Just put this file in your wallet data directory and restart your wallet. Now instead of downloading block by block using P2P connection your wallet validates and import blockchain data from this bootstrap file. Previously we’ve explained how to use bootstrap file. Here in this post we’ll see how to create this bootstrap file.
How to create Bootstral.dat file?
Some coin developers do include this file along with their latest wallet release. You’ll also find torrent files distributed by community members for the public to download and use. We’d like to remind you that never download files from untrusted source. Also remember to backup your wallet.dat and private key before making any changes to your wallet files.
If you have a full copy of blockchain that is verified and if you’d like to move it to wallet on another computer then you don’t have to generate bootstrap file. No matter if it is a Windows operating system or Linux operating system the wallet core files are the same. So just copy the chainstate and blocks folder from up to date wallet to the machine where your wallet is not updated. Anyways for some reason you might be wondering how to generate your own bootstrap.dat file. It’s actually quite simple and the following guide should help you.
Creating bootstrap file in Windows / Mac
First of all you must have a full valid blockchain data in order to create a bootstrap.dat file. In Bitcoin there is a Python Scrypt called  linearize.py which you can use to create bootstrap.dat. It will construct valid bootstrap file which will have blocks in order and contains no orphan blocks. Anyways we are not going to cover this process as bootstrap file is no longer needed for Bitcoin core wallet. Because from wallet version 0.10.0 starting the Bitcoin core and letting it to sync itself is much faster. However there are many Altcoins that still recommends to use Bootstrap.dat file to speed up the wallet initial synchronization. If you are wondering then here is how this bootstrap file is created?
To create your own bootstrap.dat file all you need to do is simply concatenate the blk files that you find in the blocks folder.
- Choose the coin for which you want to create a bootstrap.dat file.
- Open the folder where your wallet core files are located and navigate to blocks folder.
- Now read all the blkXXXXX.dat that you find in the blocks folder and concatenate them.
- Then name the final file as bootstrap.dat and optionally if you wish you can compress this file.
That’s it! The bootstrap.dat file is ready. Now in detail let’s see how it’s done in both Windows and Mac.
Windows:
1. In your Windows search bar type CMD and open command prompt.
2. Now using CD command navigate to your wallet core folder where the block files are located
For Example:
cd C:\Users\%USERNAME%\AppData\Roaming\Litecoin\blocks
3. Now in the blocks folder you’ll find several files such as blk00000.dat, blk00001.dat, blk00002.dat, blk00003.dat, blk00004.dat, blk00005.dat and so on.
Note: Some coins will have less numbers and some will have more blk.dat files. What you need to do is concatenate all these files. To do this input the following command in command prompt window once you’ve navigated to the correct blocks folder.
copy /b blk00001.dat+blk00002.dat+blk00003.dat+blk00004.dat+blk00005.dat bootstrap.dat
Once you’ve entered all the blk.dat files in sequence hit enter. Before that make sure to input bootstrap.dat at the end of the link. That’s it. Bootstrap.dat file is created and you’ll find this file in the same blocks folder.
Mac:
The procedure to create bootstrap.dat file in Mac is also same as Windows.
1. Open terminal window
2. Navigate to the folder where the blk files are located.
Ex:
cd "Library/Application Support/Litecoin/blocks/"
3. Then run the following code which will concatenate all blk files and creates bootstrap.dat file.
cat blk00000.dat blk00001.dat blk00002.dat blk00003.dat blk00004.dat blk00005.dat > bootstrap.dat
That’s all. Your bootstrap.dat file is ready. Now you can compress this file and share it to users who needs to sync their wallets faster.
Found this guide helpful? You might also like the following guides:
- How to fix wallet not syncing issue
- Importing private keys of core wallet to electrum wallet
- How to create wallet configuration file
- How to encrypt and unlock the core wallet safely
- Guide to adding nodes to your QT wallet
- Moving wallet blockchain files to another directory
- How to sign a message with Bitcoin address
It seems there is a stage missing. Are not the bootstrap files usually compressed to have one or two folders within? .dat usually isn’t a compression extension I’m aware of.