Quote from: Potato Chips on December 30, 2017, 05:53:45 PM

Signing a messsage is only available for imported addresses, If the address is a part of your HD wallet, then that feature won't be available. Quoting it with the link you provided:

Quote from: https://support.[Suspicious link removed

/hc/en-us/articles/210353833-What-is-message-signing-and-how-can-I-do-that-]
This feature is currently only available for your Imported Addresses

But there are still ways to sign a message Wink

1. Using some third party tools:

Quote from: Potato Chips on December 24, 2017, 10:27:45 PM

If the particular address is a part of your blockchain.info HD wallet, follow these steps, otherwise ignore it.

(You must have your Recovery phrase/Seed before proceeding)

First, You must get it's private key

Download this and run it offline: https://github.com/iancoleman/bip39. Paste your seed there and you will see your address/es and its corresponding private keys at the "Derived Addresses" section. To toggle between accounts, Change the number on the "account" field where 0 is your default account, it means your 2nd account will be "1" and the 3rd will be "2" and so on.. (Use Ctrl+F to easily find the address you want)

Lastly, Download this and run it offline: https://github.com/OrdinaryDude/offline-bitcoin-signer. Paste the private key, enter your message and hit "Sign"

P.S. I tested this and verified the signature through coinig

2. Importing it in another wallet and signing a message there. I recommend electrum for that

Using your seed/backup phrase:

Quote from: Potato Chips on December 23, 2017, 01:10:16 PM

Quote from: Potato Chips on December 18, 2017, 07:22:34 PM

Tutorial: https://bitcoinelectrum.com/restoring-your-standard-wallet-from-seed

*When electrum prompts you to enter your seed, Click options and tick the BIP39 Seed Box

*Please note that when importing, your funds will be accessible on both wallets which is why it's highly advisable to transfer them in a new wallet (with different seed/PK's) once the network has stabilized to avoid high fees.

Here's a tutorial to sign a message in electrum: https://www.cryptocompare.com/wallets/guides/how-to-sign-a-message-with-electrum

You can also import just one address using its private key. Use the iancoleman bip39 tool for deriving your PK's as mentioned above
Guide: https://bitcoinelectrum.com/importing-your-private-keys-into-electrum

Thank you very much. You saved me! I was looking for this information during the last week. I wrote to the blockchain.info support they still didn't answered yet. Thank you very much! Do you think it is a good idea to mover from blockchain.info to Electrum?..