I got my client stuck at 99% char data, so I reinstalled.
Usually an uninstaller takes away everything he installed, this one removed the entire folder, including all screenshots (also the JPEG ones in a folder I made within the GamersFirst/Knight online dir).

So, be aware and make a backup elsewhere.

P.S. It also sucks you cannot choose the folder where to install and the default isn't C://progra~/KO