Wallet Migration Failure May Delete Unrelated Wallet Files In Bitcoin Core 30.0 and 30.1

This problem arises specifically during the failure of migrating a wallet.dat file. To address this, the developers plan to release an update, version 30.2, which will rectify this flaw. Consequently, the binaries for the affected releases have been withdrawn from the official website as a precautionary measure.

In the meantime, it is strongly recommended that users refrain from attempting any wallet migrations through either the Graphical User Interface (GUI) or Remote Procedure Call (RPC) methods until the updated version is made available. It's important to note that this issue does not impact all users; those who are currently using existing installations, including wallets created with previous versions, should not encounter this problem and can continue their operations as normal.

The bug specifically targets scenarios involving the attempted migration or loading of a default (unnamed) wallet.dat file, a condition that has become relatively rare since such files have not been generated by default for the past five years, starting from version 0.21. A particular risk factor for triggering this issue includes enabling pruning while the wallet is unloaded during the pruning process. This information has been disseminated to subscribers of the "Bitcoin Development Mailing List" group, ensuring that developers and users within the community are aware of the potential risk and the steps being taken to mitigate it.