Lost one key of a 2-of-3 multisig wallet: what you still need to get your bitcoin out

A 2-of-3 multisig wallet is built so that losing one key does not lose the money. Any two of the three keys can sign a spend. If you have lost one device or one seed phrase, you are in the case the design was made for. Coldcard's explanation of the setup says the same thing: losing one key does not cause loss of funds, but the quorum effectively becomes a 2-of-2 (Coldcard). That means a second loss is final, so the job now is to get the funds moved while you still have two keys.

The part that surprises people is that two seed phrases alone are often not enough. This guide covers what else you need and how to find it.

Why two seeds are not the whole wallet

A single-signature wallet is fully described by one seed phrase. A multisig wallet is not. The address that holds your coins is built from all three public keys, the script type, the threshold (2 of 3), and the derivation paths. Together that is the wallet configuration, often called the wallet descriptor. Output script descriptors exist to describe exactly this, so that a wallet can be backed up and rebuilt without guessing which scripts and addresses to produce (BIP-380).

Your two surviving seeds give you two of the private keys. To rebuild the wallet you also need the third key's public part (its extended public key, or xpub) and the settings that were used to combine them. Coldcard lists the descriptor as something to back up separately from the seeds, and warns that recovery gets significantly harder without it (Coldcard).

Some wallets make this easier than others. Electrum multisig wallets are built from each cosigner's seed plus the other cosigners' master public keys (Electrum documentation). Wallets that sort keys in the standard order (BIP-67) will derive the same addresses from the same keys and threshold, so no provider has to hold extra state for you (BIP-67). That helps, but you still need the third xpub.

Step 1: Stop and copy what you have

1. Do not move or reset anything yet. Do not restore a seed into a new wallet "to see what happens" on a phone or website.
2. Make a second copy of the two surviving backups and keep them in separate places. You are now one failure away from a lock-out.
3. Write down what kind of wallet it was: Electrum, Sparrow, Specter, Casa, Unchained, Nunchuk, a hardware vendor's own multisig, or Bitcoin Core. The software decides where the configuration lives.

Step 2: Find the wallet configuration

Look in every place the setup could have left a copy:

• The wallet software's own file. Electrum keeps the wallet as a file on disk; its multisig wallet holds the cosigner public keys inside it. Other multisig software keeps its own wallet files too; check its export or backup menu.
• A configuration or descriptor export. Files with names like *.json, *.txt or *.bsms saved at setup time. Search old drives, cloud folders, email attachments and USB sticks.
• A PDF or printout from setup. If you used a multisig vault service such as Casa or Unchained, check your email and account for any setup or recovery document it gave you. Customer support links for popular wallets can help you find the right channel.
• The microSD card or screen of a hardware signer. Some signing devices store the multisig setup file you imported at the start.
• A password manager note with a long string beginning with wsh(, sh(wsh( or multi(, or three long strings beginning with xpub, Zpub, Ypub or similar.

If you find all three xpubs and know the script type and derivation paths, the configuration can be rebuilt.

Step 3: Rebuild and look, without spending

Load the two seeds and the configuration into wallet software that supports multisig and can run offline or watch-only, such as Sparrow, Specter or Electrum. Check that the first receiving address it shows matches an address you know belonged to the vault. A match means the configuration is right. A mismatch usually means a wrong script type, a wrong derivation path, or a missing key, not lost funds.

Only seed phrases and descriptors from your own backups belong in this step, and only on a device you control. Never type a seed into a website, and never send one to anyone who offers help.

Step 4: Move the funds to a new setup

Once you can sign with two keys, create a new 2-of-3 wallet with three fresh signing devices and new seed backups, back up the descriptor this time, and send the funds to it. A wallet that has lost a key is a 2-of-2 in practice, so do not leave money in it.

When the configuration is missing

This is the common failure. It usually looks like one of these:

• You have two seeds and no idea what the other xpub was.
• You have the xpubs but not the script type or derivation paths.
• The third key was on a device or in a service you can no longer reach.

Some of these are recoverable by testing combinations. If you know the third key's public part, trying the standard script types and paths is a short search. If the third xpub is gone entirely, the situation depends on whether the missing key's seed or any copy of the wallet file still exists. Do not assume the worst until the old computer, phone and email accounts have been searched, because Electrum files and exports are often sitting on a disk nobody has looked at. The same hunt applies to deleted wallet files.

Do not do these

• Do not sweep funds from the wallet to an address someone gave you. Unsolicited "recovery" offers in forum replies and direct messages are the standard scam. How to tell a legitimate recovery service from a scam is the checklist.
• Do not share a seed phrase to prove you own the wallet. A description of the wallet type and what you hold is enough for an assessment.
• Do not pay upfront to anyone who has not asked what software, script type and backups you have.

When to get help

If you hold two keys and some of the setup, but the configuration will not rebuild, or you are unsure which seed is which, describe what you have. Include the wallet software, roughly when you set it up, what backups exist for each key, and whether you have any export or PDF. Do not include seed phrases or private keys.

The related Electrum cases (2FA and multisig wallets) are covered on the Electrum wallet recovery page, and seed problems more broadly on seed phrase recovery. Assessment is free, pricing is published, and there is no fee until your crypto is back.

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