Which precautions should a newbie like me do when exporting keys from an Bitcoin Core wallet to an Electrum wallet I have an Bitcoin QT v0.8.5-beta wallet (downloaded in 2013) which it seems that I now have sucsessfully upgraded to the latest Bitcoin Core wallet. The  Bitcoin QT wallet did not disappear with the upgrade, and now I also got the Bitcoin Core Testnet wallet that automatically followed the Bitcoin Core wallet upgrade.

About 1/15 of the blockchain is now downloadet in the wallets, and I bought half a bitcoin in 2013 that I do not have catched in in my wallet yet. So I plan to download an Electrum wallet, and then import the private keys from the Bitcoin Core wallet, to the Electrum wallet, so I faster can get my half an bitcoin. 

The Core wallet has now, for some hours, reindexed blocs on disc, so I think I should wait until that is ready.

My Bitcoin Core wallet is encrypted with a password, So should I decrypt the wallet before exporting the keys? The problem then is then that I can not find a place in the  Bitcoin Core wallet to quit the password, but only change the password.

And is it a problem that I do not have catched in the whole blockchain yet to the Core wallet before exporting the keys?

Should I export the keys from the Core wallet, or should I import the keys from the Electrum wallet, and where in the right wallet do I find the option?

Other problems a Newbie like me can stumble upon at this project?
Before you begin any of this, I recommend you backup your .dat files just in case something goes wrong.

Your wallet.dat file is located at %APPDATA%\Bitcoin\wallet.dat. Make a copy somewhere safe until this operation is complete.

You're going to want to export your private keys from Bitcoin QT and sweep your private keys in Electrum and you should be golden!

The process of dumping your private keys require you open a console (Bitcoin QT -> help -> debug window -> console), unlock your wallet (walletpassphrase "your walletpassphrase here" 600), and type the command dumpprivkey [your Bitcoin address here]. You can then lock your wallet with walletlock.

With your private keys saved now, you can sweep them with Electrum by opening the sweep menu (Wallet menu -> Private Keys -> Sweep), entering your private keys while leaving the 'Address' field unchanged, and executing the dialogue.

Enjoy your new light-weight bitcoin client.