File slack is the disk space from the actual end of a file up to the end of the last cluster used by that file. When BCWipe shreds slack space of some file, the program needs to open the file for writing and then overwrite the slack space of the file. Then BCWipe restores the file's original attributes, including date of creation/modification. So when wiping file slack, BCWipe does not change the file's contents or its attributes.

Many system folders are accessible as 'read-only', so BCWipe cannot wipe slacks on these folders and it reports numerous 'Failed' records in the log file.
You can assign some folders to be skipped during file slack wiping. Please do the following:

 

  1. Run 'Wipe free space' command, go to 'Wiping options' tab and check the 'Use skipped list' box.
  2. Click 'Edit/View skipped list'.
  3. Check the 'Skip windows folder' box in the displayed window.
  4. The same is true for files from the 'Program Files' folder, so you should check the 'Skip program folder' box as well



Note that the 'skipped list' is assigned for both 'file slacks' and 'directory slacks' operations.


Note that if you skip some folders, private information may remain inside the file slack space. For example, you've just deleted a sensitive file and then the Windows Update process has started and occupied the space. Now the 'wipe free space' operation won't wipe this sensitive file because the space is no longer free, and the 'wipe file slack' operation won't wipe it because you skipped the Windows folder.

Even if you don't skip any folder, the security hole exists because Windows doesn't allow BCWipe (or any other application) to open some system files for writing. As a result, BCWipe cannot wipe the slack space and honestly reports it in the log file.

So what is the solution?
The best solution is to enable Transparent Wiping so you don't need to worry anymore about sensitive information residing in file slack space or free space.