Re: You can't import a key pair that's been used before? What?
It shouldn't be right. Perhaps what they mean is, Bitcoind/Bitcoin-qt will rescan the blockchain so it can retrieve any spendable outputs and display your balance.
Hope so. I'm testing now. It sure takes a lot longer than a minute or two if you don't have a very fast computer. And if you stop it in the middle of the scan you can corrupt your blockchain and/or wallet.
