Getting old wallet.dat files to work

Hey folks! I came across some wallet.dat files and I’ve already downloaded Bitcoin Core and synced the entire Blockchain. After syncing one of the wallet.dat files, it shows a balance of 0. What’s puzzling is that on the right side, under Last Transactions, there are multiple entries with dates and times, a [+XX.00000000 BTC] notation, and a mining symbol. There’s also an empty bracket () below the date. Is there a way to access those mined BTC? I’m pretty new to this, so please be gentle. Thanks a lot!

Were that wallet.dat files you owned and where you mined coins yourself or did you "find" some wallet.dat files somewhere in shady places of the internet? If you have a non-pruned blockchain (to avoid having to download all blocks again) you can load such a wallet.dat and execute the command "rescanblockchain 0" in the console of Bitcoin-Qt. Such a rescan for valid transactions of a wallet can take a while, so be patient. You can also execute a rescan from the command-line if you prefer that (load your wallet before execution!): bitcoin-cli -rpcclienttimeout=0 -rpcwallet="name_of_your_wallet" rescanblockchain 0 It's likely that your mined coins' blocks weren't accepted by the consensus blockchain and thus never came into existance. This can explain the zero balance when there is no spending transaction found on the whole blockchain.

If this is your wallet.dat file, I think your Bitcoin core isn't fully synced yet. Do you know how much space you need to fully sync the bitcoin core? If you have more than 628.74 GB of hard disk space, you should check your Bitcoin core folder to see if you downloaded the entire blockchain. To check if you have a balance in your wallet, copy and paste the BTC address into any explorer. If you still have funds in your wallet, you should be able to view its details. If you see this "dates and minutes, a [+XX.00000000 BTC]" with a mining symbol that is mined coins but are you sure that you own this wallet?

Hello, Thank you for the responses. Yes I am sure that this is not a random found wallet in some shady places of the internet. The Blockchain is fully synced, I waited a few days for that. To open a wallet.dat file it usually takes ~10hours. “It's likely that your mined coins' blocks weren't accepted by the consensus blockchain and thus never came into existance. This can explain the zero balance when there is no spending transaction found on the whole blockchain.” This caught my attention. So there were some actual Bitcoins mined but it did not got “verified” by the blockchain, to say it in simple terms? Is there any possibility to do that retrospectively?

Your node mined blocks that weren't properly propagated and accepted as valid blocks by other nodes in the Bitcoin network. The wallet with the "supposedly mined" coins didn't properly sync with the rest of the netword and was saved in an unsynced state and not synced properly later anymore. No, you can't do that retrospectively as that would mean to rewrite the blockchain (some earlier blocks that were confirmed long ago) and this won't happen. The coins never existed for the rest of the Bitcoin network or blocks got orphaned.

It could also be a RegTest, TestNet or an Altcoin wallet.dat file where it's quite easy to mine blocks. You've loaded it without any issue because that may have been once loaded to an older version of Bitcoin Core when there's no "cross-chain warning" prompt (before #18554) Or you're using "--walletcrosschain". To Test: It's fairly easy to test if it's a Testnet wallet.dat: Just paste the "Transaction ID" of one of the transaction containing coinbase (with mining icon) to a testnet BlockExplorer. (Right-click->Copy transaction ID) Here: https://mempool.space/testnet or https://mempool.space/testnet4 For the possibility of an Altcoin wallet, paste the txid in a multi-coin BlockExplorer like: https://blockchair.com/ Although not all Altcoins are supported there. If it found a matching transaction, it belongs to that chain, not Bitcoin.