By the way, I don't know if it comes from a system failure relative to my computer, but when I try to cut or copy the Underground's file from the original unziped folder to move it in another one, something prevents me to proceed, a warning message tells me that it's original location could not be found, the file no longer exists and I have to check its actual location, while the file does indeed exist (I can access to it and launch the tracks with my player)...
It's the first time that I experienced that kind of weird issue, did someone else had the same?