I'm running Bitcoin Core on Linux and it seems I have a single corrupted block file which is causing problems. It's taken me 2 weeks to download 75% of the blockchain, so I'd like to replace the individual block itself and duplicate the entire chain into a new folder if I can, rather than start again from the beginning. My guess is for somebody who isn't a Linux noob this would take moments but I still get lost quite fast ATM! The block file in question is blk02425.dat What I can't seem to do is download a single block on its own in the necessary format. Noob-centric help most welcome and if you like please send a lightning address and I'll zap some appreciation.

  • 1
    Can you post log files that show the error you are encountering?
    – chytrik
    Commented Apr 18, 2023 at 17:36

1 Answer 1


Upon checking my node, the file blk02425.dat has a size of 127 MB. While it might be technically possible to share and download this file online, I would not recommend doing so. Note that the file does not consist of just one block, but rather has numerous blocks compressed and combined in a specific format. The format of data can vary depending on the specific version of Bitcoin used to create it.

Don't Trust, Verify: For ensuring the accuracy of blockchain data on your node, I would recommend you to use your own hardware and follow the standard synchronisation process to download and verify the complete blockchain data.

It is an intriguing idea to consider if an attacker would be able to manipulate and inject inaccurate transaction data into a node through this method. Such an attack would require significant technical expertise. Any attempts at such an attack would be likely heavily scrutinised and detected by the wider bitcoin network, which could result in the banning of your node.

Would you rather wait for the complete download and verification of the blockchain by your hardware over one month or take the risk of your node getting banned and operating your node with incorrect data?

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    A bitcoin node builds the blkxxx.dat files as it hears about new blocks on the network, and it will most likely not hear about those blocks in sequential order. The result is that every node will have a unique set of blkxxx.dat files, as they will have received blocks in a unique order. So copy/pasting a subset of those files isn't going to work, in any case. What OP is asking about is different though: re-writing a single block's info, with the assumption that OPs node will then still validate this block's info itself (ie, not just trusting someone else's file).
    – chytrik
    Commented Apr 18, 2023 at 17:34

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