unknown space occupied by windows xp partition

Question

Hi, My windows xp (C drive) partition is 27 GB. Now it shows free space is only 2.3 GB. But when I calculate all the space using any software or manually (by adding all the folder sizes including hidden files) I get ~13.xx GB full. That means another 13.xx GB should be free.

Also while using ubuntu, I see 13.4 GB free in "Disk Usage Analyzer"

If I consider the "pagefile" as an extra space then say another 2GB is gone. Left 11 GB.

Then why it has only 2.3 GB left??!! Where are rest of the 11 GB spaces ?? How to get that space back? Any idea?

FYI I am pretty sure there is no virus or Trojan (at least published ones) in my notebook.

Thanks in advance.

Answer 1

Do you have system restore enabled on your machine? If enabled, Windows will use "free space" to save system files, app files, etc. to save different versions incase of a user or system initiated system restore.

http://vistasupport.mvps.org/decrease_storage_space-allocated_to_system_restore.htm

Answer 2

First, you're going to lose at least a little space to the file allocation tables themselves. Think of it as a big table that tells your computer where on the hard drive to find files physically stored.

Second, how many actual files do you have stored on the computer? If you've got hundreds of thousands of small files, your partition's configured block size could be causing your hard drive to fill more, even though the size of the files isn't as big. Big block size results in a lot of wasted space if you have tons of tiny files all over the place.

I'm sure there are other contributing factors, but these are the two that stuck out to me the most.