BitcoinTalk user called Stone Man reported losing 8,999 bitcoin over 16 years ago. He had bought 9,000 bitcoin, backed up his wallet, and then sent one bitcoin to himself while using a temporary Linux environment. The transaction sent the remaining 8,999 bitcoin on accident to a newly generated change address. Its key was not in the earlier backup. After shutting down and restoring the saved wallet, he could access the one bitcoin. The backup existed. It simply did not contain the key created after it was made. Today, the bitcoin would be worth $647,647,440.