Quote from: Waldschrat on March 05, 2015, 05:04:30 PM

Right now I'm using Bitcoin core and I want to use Electrum. What this procedure work with this combination?

This is a bad idea for a couple of reasons.

First of all, any addresses that you import into Electrum will NOT be able to be recovered from the Electrum seed. Therefore, if you ever need to recover your Electrum wallet, and you use the seed to do so, you will have lost all the addresses (and associated bitcoins) that you imported.

Second, addresses really aren't meant to be re-used. It is best to use a new address for every transaction. Re-using addresses reduces your privacy, and reduces the privacy of the people that you do business with. It also slightly reduces your security. If you are already using a new address for every transaction, then there is no need to import any addresses.

The best thing to do would be to create your Electrum wallet and then send all of your bitcoins from your Bitcoin Core wallet to a new address from your Electrum wallet. Then back up your wallet.dat file from your old, and now empty, Bitcoin Core wallet, just in case anyone accidentally re-uses one of those old addresses to send you bitcoins.