Since 5 Jan 2026 the Bitcoin Core team has been warning that versions 30.0 & 30.1 contain a wallet-migration flaw that can delete entire wallet files and leave users without access to their coins.
What you need to know:
• Who is hit – only people who try to migrate an old “legacy” Berkeley-DB wallet that still lives in a custom -walletdir and has never been renamed or upgraded.
• What goes wrong – if pruning is enabled, the migration code mis-parses the directory and removes every file inside that wallet folder, not just the old wallet.
• Who is safe – modern descriptor wallets, hardware wallets, and anyone simply syncing the chain or running the GUI without a migration.
• Official action – binaries for 30.0/30.1 were pulled from bitcoincore.org; a fix is expected in 30.2 [^0^].
• What to do now
– Do NOT attempt a wallet migration with 30.0/30.1.
– Back up the entire wallet-directory (and wallet.dat ) before any future upgrade.
– If you already upgraded, check backups; if you don’t have one, keep the node offline until 30.2 is released and seek help on the Core-issue tracker.
The bug is local-only—the Bitcoin network itself is unaffected—but for affected users the impact can be total loss of funds if no backup exists.
