Six mistakes that cost owners bitcoin when cashing out: wrong network, wrong address, early P2P release and more. What to do instead.
Basics
Almost every loss at cash-out comes from the same short list of mistakes. None of them needs technical skill to avoid. Each needs one habit. Here they are, with what goes wrong and what to do instead.
What goes wrong: the exchange's deposit screen offers several networks for BTC and you pick one that is not Bitcoin, such as BEP20, or you copy an address for another network. Your wallet sends on the Bitcoin network, the exchange is listening on another, and the deposit never arrives.
Do this instead: choose Bitcoin as the network on the exchange and in your wallet. A Bitcoin address starts with bc1, 1 or 3. If the address starts with 0x, stop. Use another network only if the exchange's deposit screen tells you to and your wallet holds bitcoin on that network.
What goes wrong: an address is typed by hand, copied from an old message, or replaced by malware that swaps whatever you copy for a thief's address. The transaction is valid, final and goes to someone else.
Do this instead: copy the address from the exchange's deposit screen each time, paste it, and compare the first six and last six characters. Send a small test amount to every new address and wait for it to be credited before you send the rest. See Send bitcoin from your wallet to an exchange.
What goes wrong: a buyer sends a screenshot of a transfer, says the bank is slow and asks you to release. You release, the money never arrives, and the bitcoin is gone. Or the money arrives from a stranger's account and is reversed later.
Do this instead: release only after you have opened your own banking app and seen the full amount, available, from the buyer's own name. A screenshot is not proof. If anything does not match, do not release and open an appeal on the order. See Binance P2P: sell for local currency.
What goes wrong: you saved a deposit address months ago, or set it as your mining payout address, and the exchange has since rotated or expired it. Deposits to the old address are delayed, need a paid recovery, or are not credited at all.
Do this instead: before each transfer, open the deposit screen and check that the address shown is the one you are about to use. If payouts go straight to an exchange, ask the exchange in writing whether the address is permanent, and check Earnings against your exchange balance every month. See Set your payout wallet.
What goes wrong: you post a question in a public group, or simply hold an account, and someone writes to you as support from the exchange, the wallet maker or Firsthand Bitcoin. They are friendly and quick. They ask you to validate your wallet on a website, to share your screen, to install an app or to type your seed phrase. Everything in the wallet is taken within minutes.
Do this instead: treat every support message that comes to you first as a scam. Contact support yourself, from inside the official website or app. Never type your seed phrase anywhere except into your own wallet device when restoring it. Firsthand Bitcoin will never ask for your seed phrase. See Seed phrase safety.
What goes wrong: a year of mining, card payments and P2P sales goes by with no records. At tax time nobody knows what was mined on which day, what it was worth, or what each sale brought in. Rebuilding it afterwards is slow and expensive, and exchanges can limit how far back you can export.
Do this instead: once a month, download your exchange history and save it with your Firsthand Bitcoin Invoices and Earnings. Note date, BTC amount, price and money received for every sale. Tax rules differ by country and by person: ask your accountant early, not in the week the return is due. See Tax records for mined bitcoin.
Careful: If something has already gone wrong, do not accept help from anyone who contacts you. Recovery agents who write to you after a loss are a second scam. Contact the exchange's support from inside its official site, give them the txid, and write to hello@firsthandbitcoin.com if your payout address is involved.