How do I transfer btc from Core that never finishes syncho to another wallet? My Core finished sychro after 4 months, the transaction was visible finally (then I moved all data from one file in the computer to another) and Core started synchro again with 3 yrs remaining. It shows no transactions now. 

How do I get the funds from there to another wallet, I have the receiveing address from BTC.
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Even though your wallet is still syncing you can use the debug console or bitcoin-cli along with dumpprivkey to get the private key of one of your wallet addresses. You can then import the key to an SPV wallet.