Bitcoin is a Peer to Peer cryptocurrency. The wallet client of Bitcoin downloads blockchain from the network by syncing with other nodes. Not just Bitcoin but most of the cryptocurrency core wallet works like this as they are all based on Bitcoin. Since it requires Peer to Peer communication to download and validate each blocks the process of synchronizing the whole blockchain will be slow. Even computers with high Internet speed will take days or even weeks to sync the Bitcoin blockchain. This is a problem with Bitcoin and other cryptocurrency wallets whose blockchain file size is huge. You can add nodes to your wallet which will help with the network connection but it doesn’t speed up the synchronization process. Fortunately, to accelerate the wallet synchronization process you can use Bootstrap file.
What is Bootstrap file and how it works? Where can I find Bootstrap.dat for Bitcoin and how to use this file?
What is Bootstrap.dat?
Bootstrap.dat is a file that contains the copy of blockchain from genesis block to a certain point of time. This compressed Bootstrap.dat file is used to speed up the initial blockchain download times. How? Your wallet client downloads and verifies each blocks from the P2P network. This is usually slow and especially if you are using wallet for the first time then syncing process can take quite a long time.
Instead of using Peer to Peer communication your wallet client can read blockchain data from this compressed bootstrap file which contains the copy of blockchain data until a certain block height. Once the wallet client completes reading data from bootstrap file, it will then use the P2P connection to download the remaining blocks. This method is faster and moreover it consumes less bandwidth compared to standard synchronization process. However still bootstrap method takes some time as your wallet client needs to validate each individual blocks.
Where can I find this Bootstrap.dat file for Bitcoin?
First of all we’d like to let you know that downloading bootstrap.dat file for Bitcoin from unofficial and untrusted source is highly not recommended. This recommendation is not only for Bitcoin but for other crypto currencies as well such as Dash, Litecoin, etc. You’ll find bootstrap.dat file in torrent, Bitcoin Talk forums and in several third party websites. But as we said these are unofficial sources and they are maintaining it for research purpose. So where can I find the official bootstrap.dat file for Bitcoin?
Bitcoin.org used to provide this bootstrap file to accelerate the synchronization process. But that file is not available and they no longer maintain it. Because syncing wallets using bootstrap.dat method is no longer advantageous and is not necessary anymore. As of Bitcoin Core version 0.10.0 and later downloading blockchain using peer to peer network is much faster and downloading blockchain directly using core wallet client is much efficient.
More information: https://bitcoin.org/en/release/v0.10.0#faster-synchronization
How to use bootstrap file to speed up initial synchronization
While Bitcoin no longer uses this method other cryptocurrencies recommends this and they maintain this file officially. You can find the package either in official website or at their GitHub repository. This compressed bootstrap.dat file contains serialized copy of the blockchain and you can use it to speed up your wallet’s initialization process. If you ever come across such file then here is how to use the bootstrap file.
1. The most recommended step before making any changes to your wallet is taking wallet backup. Have a copy of wallet.dat file in two or more locations. If your wallet is new or empty then this step is not required. Once backup is done exit the wallet.
2. Now find the official source and download the bootstrap.dat file which is usually a compressed zip file.
3. Once the .zip file is downloaded, unzip it where you’ll find the file named bootstrap.dat.
4. Next you need to move this bootstrap.dat file to your wallet core folder. All cryptocurrency wallet maintains its core files at the following location.
Windows: C:\Users\%username%\AppData\Roaming\coinfolder Mac OS: ~/Library/Application Support/coinname Linux: ~/.coinname
If your wallet files are not there in default data location then during installation you have opted to use a custom blockchain directory.
Find the directory and just put the bootstrap.dat file there. Once done open your wallet.qt file and at the bottom left corner instead of “Connecting to Peers” you will see “Importing blocks from disk”.
But I’m using this wallet for a long time and in core folder I have some block files. Should I delete all these .blk.dat files before using this bootstrap file?
Importing bootstrap.dat to existing wallet?
First of all bootstrap.dat files are to speed up the initial blockchain download times and is not necessary if you are already using wallet. Anyways if your wallet is stuck at certain block height and if you wish to start over then you can use the bootstrap.dat file. But before using that to import blockchain here are few files and folders you need to delete first.
First close your wallet if it is already running. Then head to your wallet core folder and copy the wallet.dat file to another location. This step is a must especially if you have funds in your wallet. Next delete the folders and files shown in the image below such as: blocks, chainstate directory and peers.dat file.
Once done move the bootstrap.dat to this location and then launch the wallet. Your wallet client will now start importing blocks from disk that is it will start to process blocks found in the bootstrap.dat file.
Note: This process uses high CPU resources and it will take some time. During this period do not attempt to use or close the wallet as you might end up crashing it. Once your wallet client completes importing blocks from disk it will then connect to peers and start downloading the most recent blocks.
Can I delete this bootstrap file?
Yes, once your wallet finishes downloading the blockchain data you can go ahead and delete this file. Actually you won’t find the original file which you dropped into the core directory. Once the wallet have copied and imported the blockchain files it will mark bootstrap.dat file as bootstrap.dat.old. This old file is no longer needed and so you can delete it.
Is this file safe?
Using bootstrap file for Bitcoin is not recommended as syncing directly using wallet client is much faster and robust. Anyways you still have this question as most other coins recommends using bootstrap file to speed up their wallet synchronization process. This bootstrap.dat file only contains blockchain data, it is safe and it doesn’t affect your funds in anyways. However as we previously said never ever download and use bootstrap.dat file from untrusted / unofficial source as the file could potentially contain malware.
Hope it helps!
Do like this article? You might also like reading about Bitcoin blockchain pruning.