Seems that many people become scared as soon as they seen 1 week or over and discover they've to download the full blockchain(ca. 60 GB now required), so it's full of question about migrating from bitcoin core to electrum? But what about vice versa? Bitcoin core doesn't support sweeping, but it should support, by command line, importing private addresses. First questions, I read there is dumpwallet, is there a importwallet option that allow to import more than 1 private key at time? This could be a simply option, import all keys at time. Import each keys with importprivkey can be a long operation. Then, 2nd option, is just send electrum btc to a bitcoin core address right? What about get the electrum wallet, is bitcoin core able of read it in some ways (not with external software)? Is there a way to safely convert?