I get fatal error when using the blockchain files so looks like I have to download the blockchain manually 
Once with other coin, not KTK, I got an error on my virtual Windows XP when I tried using blockchain from the Windows 7. On another Windows 7 this blockchain loaded fine. The problem was with the index file.
Solution.
1. You can rename new blk0001.dat to the bootstrap.dat and start the wallet.
2. You can use the option -loadblock=c:\new\blk0001.dat - loading blocks from blk0001.dat to the wallet blockchain.
You should remove old blockchain before updating.