In addition, some users also added another strange thing in forums: if they right-click on the C drive and view its properties, it will show that the hard drive is almost full. Can't find mega-files (even in an in depth search), have already moved files off the drive and it keeps filling. Here is a true example we extract from : Q: 1TB Drive Keeps Filling Up - FASTįor the past few days, my 1TB hard drive has been filling up rapidly - taking up as much as 100GB in a few hours. Although they don't store any more files on the drive, and even if they delete some files, their C drive keeps filling up. While browsing Windows forums, we find many users report their hard drive space disappearing.