text: The rest of the partition may be used by the swap file which is not reported in Explorer.  Try reducing your swap file size.\n\nAlso, depending upon the sizes of your files, they may be taking up more disk space than the actual totals of the files.  In short, the file system can only write in fixed-length blocks (I think NTFS default is 64K).  If a file does not occupy the entire block, the rest is not used...the next file must be written to another block.  If you have tons of small files on your hard drive you may be using much more than the total sizes of the files.  There's not much way around this other than moving the files to another partition with smaller block sizes.\n\nFinally, some applications (like Photoshop) actually reserve block of space on the hard drive as "private" swap space.  This guarantees the application will always have a work area on the disk while its operating.  Check with the software vendor for some of your applicationsto see if this is the case and if you can either resize the reserved block, or move it to another drive.