- Legacy wallets are at risk of being deleted during migration with Bitcoin Core v30.
- Back up wallets and the data directory before attempting an upgrade.
- Modern wallets and hardware wallets are largely unaffected.
A critical bug has been discovered in Bitcoin Core v30, raising alarm for users planning to upgrade their wallets.
The issue specifically affects the wallet migration process, which is intended to transfer older wallet files into the latest software format.
Under certain conditions, this migration can delete wallet files, putting users’ funds at risk.
Developers have confirmed that the bug mainly impacts older legacy wallets, particularly those that have not been renamed or updated in many years.
According to official sources, modern wallets and hardware wallets remain largely unaffected.
However, a significant risk remains for anyone running a node with outdated wallet files who attempts a migration.
Bitcoin Core wallet bug
The problem occurs when Bitcoin Core attempts to migrate an unnamed legacy wallet located inside a custom wallet directory.
If pruning is enabled, the software may misinterpret the migration process and inadvertently delete all files in the wallet directory.
This is not a network-level bug, so the Bitcoin blockchain itself remains secure.
Instead, the threat is local: users can lose access to their funds if no external backup exists.
The vulnerability only triggers during a migration attempt.
Simply running the software or syncing the blockchain is not enough to cause files to be deleted.
Developers responded quickly by removing the v30.0 and v30.1 binaries from the official download pages.
Users are now urged to avoid performing any wallet migrations until a fixed release is available.
Actions users should take
The Bitcoin Core v30 wallet bug is serious but avoidable if users follow official guidance and prioritize backups.
Bitcoin Core recommends backing up the entire wallet and data directory before attempting any upgrade.
These precautions can prevent potential losses, especially for users with legacy wallets.
It is also advisable to verify whether a wallet is classified as “legacy” or “modern.”
For those with legacy setups, extra care should be taken when handling migration procedures.
Users should also confirm their directory configuration, including the -walletdir parameter, to ensure files are not accidentally removed.
Maintaining offline or external backups remains the safest way to protect funds.
Although the bug does not affect the network, the risk to individual wallets is real and immediate.
The community is awaiting the release of Bitcoin Core v30.2, which will address the migration bug and restore a safe upgrade path.
Until then, cautious users are advised to pause any wallet migrations and keep secure external backups.
This bug serves as a reminder that software updates—even those intended to improve security and performance—can introduce unexpected risks for legacy systems.
By taking simple precautions, users can avoid potential losses and keep their Bitcoin holdings secure.