Invalid Seed / Invalid Mnemonic

If the wallet is throwing that error, don't assume the phrase is gone — the cause may be a word error, an incomplete phrase or a format mismatch. Start with the word count and the exact spelling before you try anything else.

What the error usually means

• A wrong, missing or duplicated word (see wrong seed word).
• The wrong word count: BIP-39 allows 12, 15, 18, 21 or 24 words, and most wallets use 12 or 24; 11, 23 or 25 usually signals a missing or extra word.
• The phrase uses the wrong format for the wallet. Electrum seeds are not BIP-39 — they use Electrum's own versioning — so a valid Electrum phrase can be "invalid" in a BIP-39 wallet and vice versa.
• An old-format seed: Electrum pre-2.0 seeds use a different word encoding. MultiBit HD uses BIP-39 words, but historical versions can require their own derivation handling; that is separate from whether the words form a valid mnemonic.
• A phrase from a non-English word list, or a word transcribed in the wrong language.
• A passphrase or extra word is being treated as part of the seed (see forgotten passphrase).

What to try yourself

1. Check the word count and write the phrase in lowercase, single-spaced, in the exact order.
2. Confirm which wallet created the phrase and restore into the same wallet software — not a different one.
3. If the wallet offers seed types (Electrum: Legacy, SegWit, 2FA; hardware wallets: BIP-39), try the matching type.
4. Look at the words themselves: do they all come from the official 2,048-word BIP-39 list? If not, the phrase may be Electrum-style or from an old wallet format.

What is realistic

• A wrong word, wrong count or wrong format does not itself rule out recovery. What remains determines whether candidate words can be tested, a missing word reconstructed or the phrase restored in its original format.
• An old-format seed from a discontinued wallet, such as Electrum pre-2.0: identifying the format is the first step. For MultiBit HD, also identify the version and derivation scheme before assuming a standard import will show the right addresses.
• A phrase that is genuinely incomplete: see incomplete recovery phrase.

What is not realistic

A phrase that does not exist — no words written down, no partial memory — cannot be made valid by any amount of analysis. The error message will not change, and neither will the outcome.

What not to do

• Do not keep entering the same phrase in different wallets and hope: format mismatch is a diagnosis, not bad luck.
• Do not "fix" the phrase by swapping words randomly.
• Do not send the phrase to a service to "check" it. Validation should happen in software you control, offline.

When professional help changes the outcome

When the format is unclear - an old Electrum seed, a discontinued wallet, a non-standard word list - identifying it comes first. We determine what the phrase is, convert it correctly, and restore it in the right software.