Example (Bitcoin Core/Bitcoin-Qt):
"Old" files often suffer from bit rot. If your wallet.dat won't open, you may see an error like CDBException or Database Environment Error. old walletdat hot
You will need a tool called pywallet.
On the air-gapped machine, use pywallet or bitcoin-tool to dump the private keys out of the wallet.dat. You are looking for output that starts with 5, K, or L (WIF format—Wallet Import Format). On the air-gapped machine, use pywallet or bitcoin-tool
Right-click the file > Properties. If the "Created" date is between 2009 and 2014, your pulse should quicken. The earlier the date, the higher the potential reward. If the "Created" date is between 2009 and
A newly created wallet.dat is usually around 100KB. An old wallet.dat that has seen a lot of transactions could be 1MB, 5MB, or even 10MB. That size indicates many keys—and many potential coins.