Finally I was able to get my computer fixed and download a new version of Bitcoin-Qt. Now I would like to import my original wallet.dat from the old client which was encrypted into an new version of Bitcoin-Qt.
You can also import the wallet.dat directly into Electrum. Bitcoin Core needs to download the whole chain (as you mentioned) so that'll take a while. Without the chain, your transaction are indeed illegal/conflicted.
So, I got Multibit. But I couldn't import the old .dat wallet. Am I missing something?
To merge your wallets: Open Console and enter dumpwallet <filename>. Stop Bitcoin-Qt. Replace wallet.dat with your new wallet file (move the current wallet.dat file to a save place).
Edit 2: I would like to be able to manage my funds using my mobile or my desktop - both looking at the same wallet. If you dont mind using a new private key you could import a private key from your bitcoin desktop wallet, sending your bitcoins to this address for further usage.
Wondering how I can import the wallet.dat file from bitcoin-qt client to Electrum wallet offline. I would like to keep my current bitcoin-qt wallet offline and be able to do transactions from my offline computer to my online computer using Electrum.
Import Wallet Create a new wallet by importing an existing wallet file. Drag the wallet file into the area above. Supports Bitcoin-Qt (wallet.dat) and blockchain.info (wallet.aes.json) files.
Full tutorial how to export private keys and wallet.dat file from Bitcoin Core, and import private keys into MultBit.
import prof7bit.bitcoin.wallettool.exceptions.FormatFoundNeedPasswordException. /** * Wallet.dat import handler. This handler does not need any. * non-java dependency to read the Berkeley-db B-tree files.
WARNING. Before reading this page, users should note that messing with ECDSA private keys is very dangerous and can result in losing bitcoins, even long after the import. It is recommended that outside of self-generated vanity addresses, users should never import (or export) private keys.