Need Help! Can't Sweep My Grandpa's Legacy Bitcoin Key

I found a bitcoin private key from my grandpa. It’s a legacy one, starts with 5. Imported it into Titan wallet and saw the balance, but when trying to send it using Ellipal, I get "BAD PUBKEY" error. Tried Electrum to sweep, but the button is greyed out. Other legacy keys work fine though.

Titan wallet is kinda new to me but it’s weird that you can import other legacy keys into Electrum but not yours. I doubt it’s an Electrum issue. Have you thought about trying Exodus instead? Might give you a different result. Also, be careful about putting keys online.

I did use Bitaddress offline, downloaded the HTML and stayed offline. Gonna check Exodus, thanks!

Tried Exodus, but it says "Unable to Add BTC. Please try the move funds feature again in a few minutes." I waited and retried but still got the same. If I mess with the key, it tells me it's invalid, so something’s blocking me from moving the funds. The address gets small amounts though, which is odd.

Not sure what Electrum checks when sweeping. Does it only verify the key or also check if funds are spendable? Maybe try "Import the private key" in Electrum instead of sweeping it. See if that works, could give you more info.

I tried importing while making a new wallet in Electrum but still greyed out. I thought having the private key means I can access my funds. No potential locks like with other blockchains, right?

Yep, a valid private key should give you full access. It’s concerning that you can’t import it in any wallet. Maybe someone else with more experience can chime in. Just watch out for scammers trying to DM you.

Thanks, hoping someone has the answer.

Is your grandpa's private key this one: 5HpHagT65TZzG1PH3CSu63k8DbpvD8s5ip4nEB3kEsreAbuatmU? That’s actually an invalid key, outside of the valid range. Looks like Bitaddress caught an error.

Crap, that’s the key I have. Feels bad to find out it’s a known issue in the community. Thanks for the help anyway.

Every action increases risk. Using Bitaddress offline isn’t enough if you go online later. If you can’t move funds, it’s likely that key isn’t right. How did you generate that address from your key?

You figured all this out from OP’s text? Impressive! Either OP’s grandpa got scammed or was playing a cruel joke.

Best clue is the error from Bitaddress. I tested it with known invalid WIF keys and got different error messages. Seems like a solid guess that it’s a bad key. Or maybe grandpa used a faulty wallet.

Just a heads up, if a newbie comes here, make sure to check any address they post first. Lots of scams and puzzles out there. Better safe than sorry.