vWhen I open the bitcoin-qt (v0.8.5 beta) app on my MacBook Pro 10.7.5 it says - loading block index, verifying blocks, loading wallet - then immediately crashes on loading wallet to give message "bit coin-qt unexpectedly quit". I know the address of my wallet, but not the private key. How can I solve this problem ??
Find Windows PC (friends, work, family)
Install fresh bitcoin-qt for Windows and run it once and then quit
Open folder: %UserProfile%\AppData\Roaming\Bitcoin\ and replace wallet.dat file from Your Mac (overwrite)
Open bitcoin-qt again and if it start OK generate private key: Help > Debug window > Console > dumpprivkey your_wallet_address