Need help.Bitcoin lost with mycelium /Besoin d'aide.Bitcoins perdus avec mycelium

[Jean1200]

Hello, I need your help.
I installed mycelium on android.
I had bitcoins on a paper wallet of around 0.0062.
I made a payment of 0.0021 bitcoins at an online merchant by scanning my paper wallet with mycelium.
Mycelium did send the 0.0021 bitcoins to the merchant but transferred the rest of my bitcoins (0.0041) to a new btc address for which I do not have the private key and which is not in my mycelium wallet: '(
However, this public address does appear in the blockchain with my 0.0041 bitcoins… How can I recover the private key of this new address to which mycelium has sent my remaining 0.0041 bitcoins?
Thanks a lot for your help!

In french
Bonjour, j'ai besoin de votre aide.
J'ai installé mycelium sur Android.
J'avais des bitcoins sur un paper wallet d'environ 0,0062.
J'ai effectué un paiement de 0,0021 bitcoins chez un marchand en ligne en scannant mon portefeuille papier avec mycélium.
Mycelium a envoyé les 0,0021 bitcoins au marchand mais a transféré le reste de mes bitcoins (0,0041) vers une nouvelle adresse btc dont je n'ai pas la clé privée et qui n'est pas dans mon portefeuille mycelium:'(
Cependant, cette adresse publique apparaît dans la blockchain avec mes 0,0041 bitcoins… Comment récupérer la clé privée de cette nouvelle adresse à laquelle mycelium a envoyé mes 0,0041 bitcoins restants?
Merci beaucoup pour votre aide!

[OmegaStarScream]

Try to sweep the paper wallet again and see if it works. The unknown address you're referring to must be the same one you have printed in your paper just in another format (legacy/segwit).

[LoyceV]

I made a payment of 0.0021 bitcoins at an online merchant by scanning my paper wallet with mycelium.
Mycelium did send the 0.0021 bitcoins to the merchant but transferred the rest of my bitcoins (0.0041) to a new btc address for which I do not have the private key and which is not in my mycelium wallet: '(

It depends on each wallet how they handle change when spending from a paper wallet. For this reason, it's always recommended to sweep the entire balance of any paper wallet. I've never tested how Mycelium does this.

I'm just guessing here: if you click the ACCOUNTS tab, does it show you more accounts? Maybe Mycelium sent the change to your Bitcoin HD account.

The unknown address you're referring to must be the same one you have printed in your paper just in another format (legacy/segwit).

I hadn't considered that, but it would make sense! Mycelium asks which address format you want to use when you create a new private key, and even lets you switch between formats.

[HCP]

Mycelium did send the 0.0021 bitcoins to the merchant but transferred the rest of my bitcoins (0.0041) to a new btc address for which I do not have the private key and which is not in my mycelium wallet: '(

I just tested this (with TestNet)... I created a "paperwallet" (using the TestNet version of bitaddress)... then sent 0.1 tBTC to it (from Electrum)... then I selected the "Cold Storage" option from Mycelium menu, tapped "QR Code" and scanned the QRCode of the private key generated on bitaddress...

It detected the 0.1 tBTC, I setup a transaction for 0.0123456 tBTC and sent it back to a new address from my Electrum wallet... Looking at the transaction created by Mycelium, the "change" was sent back to the original paper wallet address:



So, I'm not sure what happened in the OP's case? Maybe just rescan the QRCode from the paper wallet and see if it finds the correct address/coins? Mycelium says after you scan the QR Code that it is "using a private key with the following Bitcoin address:" and then lists the Legacy, Nested SegWit and Native SegWit addresses generated from that private key.