Bitcoin Core v30 wallet migration bug can delete legacy wallet files

Bitcoin Core developers warned on Monday that a wallet migration bug in versions 30.0 and 30.1 can delete files and result in fund loss when migrating certain legacy wallets. According to Cointelegraph, market analyst Lacie Zhang said the issue is triggered when the software attempts to migrate an unnamed legacy "wallet.dat" stored in a custom wallet directory (often set with "-walletdir") while pruning is enabled.

In those cases the migration can appear to complete, but cleanup logic can mistakenly delete the entire wallet directory, and without an external backup "loss of access to funds is effectively guaranteed," the outlet reported. Community lead Shawn Odonaghue told Cointelegraph the bug mainly affects "very old wallet setups" and that hardware wallets or modern wallet software are unlikely to be impacted.

Bitcoin Core pulled the 30.0 and 30.1 binaries from its official download site and advised users not to use the wallet-migration tools until a fixed release, Bitcoin Core 30.2, is available; the project said nodes not attempting migrations can continue running as normal. Zhang said technically proficient users can check exposure by confirming their client version, whether their wallet is legacy, inspecting "debug.log" for pruning and migration activity, and reviewing whether "-walletdir" points to a custom location, and she urged immediate external backups if no migration has yet occurred.

Key Topics

Crypto, Bitcoin Core, Legacy Wallet, Wallet Migration, Pruning, Lacie Zhang