So I wrote the Myth TFL installer (not this one). The reason this happened is because you could install other maps and whatnot, and to make the uninstall clean, we had to recursively delete your data folder. In the sequel, somehow that code (which did sanity checks) was used to delete the applications directory, instead of just the data directory in the applications directory. So if you installed it on C:/, it would delete everything recursively from there. Nowadays, uninstall usually leaves any user installed files (like saves or downloaded content) but at the time, as the article suggests, hard drive space was more precious. Also, I wasn’t there for this issue, so I don’t know the above for sure, but having written the previous installer, I’m pretty confident that’s what happened.