Bitcoin Forum

I had created a standard electrum wallet with great success, and then started reading about the advantages of multisig wallets.  Apparently, I did not read enough as I decided I was going to be clever and try and set up a multisig wallet using the Coinbase Multisig Vault as the cosigner on an electurm [2of2] wallet.  I sent some btc to my Electrum Wallet and it was successfully deposited, but now whenever I try and send any btc I cannot verify/complete the transaction.  All that currently shows is that the transaction has been partially signed (5/10).

It was not my most intelligent moment.  Any help would go a long way.

What I have:
- Electrum Wallet [2of2] (Access to the seed and keys)
- Coinbase Multisig Vault (Access to account with Coinbase public key, Shared Public Key, User Public Key)

What I cannot figure out (or know if possible):
- How to sign the transaction out of Electrum Wallet, or recover my btc into a standard wallet.

Apologies in advance if this has been covered already anywhere else, but so far I have not seen or maybe not had the knowledge to recognize a solution to my specific problem.  To anyone who finds a solution I will send you some btc!  Thanks again!

what do you mean 5/10? If it's a 2 of 2 multisig wallet then it should 1/2 not 5/10.

which coinbase multisig vault key did you use? Was it the one labelled shared key or user key in the graphic here:

https://www.coinbase.com/multisig?locale=en-US

If it's the shared or user key then you can just create a new multisig wallet with that xprv and the seed that electrum generated for you. Use file > new/restore to begin the process.

Hey there. Actually I've never attempted the exact situation you have (Electrum and Coinbase) but assuming that it should work just the same as using 2 Electrum. Just to confirm (and sorry for assuming), did you correctly set up Coinbase to be the co-signer? Ie. both addresses on Electrum and Coinbase are the same? Because if not, I think you can still create the second Electrum 2of2 wallet (say in a USB stick) enter the Wallet1 master key and then you're ready to try again, co-signing from wallet2.

Otherwise, just try saving the partial tx and then load it from Coinbase (I don't use CB so don't know how this works) or scan the QR code with the Coinbase wallet. That should let you complete the second signature.

I used the User Public Key.  And in regards to 5/10 it seems to depend on the amount of btc I attempt to send.  For example, sending most of what is in the wallet, (around 1 btc) opens up a window with Partially signed (5/10), as well as 5 inputs.  At .05 it is (1/2) with only one input. 

I will attempt the restore option and report the results.

Unfortunately, it still looks like I am unable to sign the other half of the transaction.  Whenever I try and send something from the Electrum Wallet, I get to the this stage: http://imgur.com/xSHWJ33 (http://imgur.com/xSHWJ33)

I am not sure how to proceed from here.

At this step, you need to complete the tx by signing from the other wallet. You still didn't reply to my questions above so I don't know if you set it up right. But you can try this anyway from here and see if it works.

Click the "SAVE" button to save this tx as a file. Then use your other wallet to LOAD the file created. If that worked, you should be able to sign and broadcast.

OR use the QR code (in between the COPY and SAVE button) and simply scan it from the other wallet. Sign and broadcast. If neither of this steps work you need to respond to questions above to confirm you set it up right in the first place.

Sorry about that!  To be honest,  I created this wallet in 2015 and thought the flash drive was lost so I am not exactly sure I created it correctly.  I cross checked the addresses listed on the Electrum wallet and on Coinbase and they are not the same. I will attempt to send the coins via the method you suggested.  Thank you!

Please ignore the other guy. Your addresses can't possibly be the same because according to the OP your electrum wallet is a multisig wallet between electrum generated seed and coinbase's extended public key. Coinbase knows nothing of your electrum wallet so the addresses can't possibly be the same.

What you need to do is create a new wallet like this:

file new/restore > enter name for your new wallet, click next,

select multisig wallet, next

from 2 require 2, next

select "i already have a seed", next

enter your seed from your electrum wallet, next, next,

select  " enter cosigner key", next

now past the xprv for the user key from coinbase. the xprv is the master private key or extended private key not the extended public key. it has to be the xprv of the User key in your coinbase wallet because it that key's public component that you used. if there is no option to get the extended private key then you are in trouble

after that you just click next next until you are done creating the wallet.


So once again you need the extended private key (xprv) of the User from your coinbase wallet. If you can't figure out how to get that then you can't be helped.