I'm trying to start geth 1.8.1-stable-1e67410e with the following command:

geth --datadir="/custom-folder-path" --rpccorsdomain "*" --rpc --dev --mine --minerthreads 2 --rpcapi="debug,db,eth,net,web3,personal,web3" --unlock "0x42d9fa1776d5041d78e13549f295601d496b297f,c5a3b476d3f0ac4ee02cc74a03e73c9bad186b32,0481de49674c6b122fcc64bcb16396b1ada47107,c682648c18cd05f46a6e927ee057f58f92e2ca7f" --password "dev-blockchain-1-pwd" --ipcpath "/custom-ipc-path"

with the file dev-blockchain-1-pwd containing the four passwords:


In the past this command successfully fired up a local blockchain, but now it outputs the following

INFO [02-19|14:55:44] Maximum peer count                       ETH=25 LES=0 total=25
Fatal: Failed to unlock developer account: could not decrypt key with given passphrase

I've successfully unlocked the JSON wallet files on myetherwallet.com with the passwords in the dev-blockchain-1-pwd.

Have you got any clue on how to deal with this? Thank you

  • Update: no solution found as of 2018-05-28, but I've also moved to other stuff in the meanwhile.
    – reallynice
    May 28, 2018 at 14:42

1 Answer 1


geth --dev creates a preconfigured private network, so --unlock and --password don't work.

If you want them to work, create a new private network and geth init it with a custom genesis.json.

  • geth --datadir data --networkid 15 --http --http.corsdomain="remix.ethereum.org" --http.api web3,eth,debug,personal,net --vmdebug --dev, it gives same error.
    – hobbydev
    May 2 at 9:48

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