Piriform
CCleaner

Wiping free disk space

When you delete a file, Windows removes the reference to that file, but doesn't delete the actual data that made up the file on your hard drive. Over time, this data will be overwritten as Windows writes new files to that area of the drive.

This means that, given the right software, someone could reconstruct all, or parts of files that you've deleted. For privacy and security reasons, you can set CCleaner to wipe the free areas of your hard disk so that deleted files can never be recovered.

Note: Wiping free space can take a substantial amount of time.

Method 1 (Automatically wipe when cleaning):

  1. In CCleaner, click the CCleaner icon at left.
  2. On the Windows tab, select the Wipe Free Space check box.
  3. CCleaner displays a warning about extra time. Click OK.
  4. Run CCleaner as usual.

Method 2 (Manually wipe with Drive Wiper):

  1. Select Tools > Drive Wiper
  2. Choose the type of wipe you require:
    1. Free Space Only will leave your normal files intact
    2. Entire Drive will erase all of the files on the drive.  WARNING, this means the whole of the partition will be erased.  The drive will still be formatted, but all data will be erased.  For safety reasons, this feature is disabled for the boot drive.
  3. Choose the type of security you require (Simple Overwrite is ok for most situations)
  4. CCleaner will warn you before proceeding

Changing CCleaner settings

To select the drives whose free space CCleaner will wipe, see this topic.

Wipe Free Disk Space limitations

CCleaner can't wipe every deleted file from your free disk space. There are some limitations, because of the way Windows stores some files.  Here are some examples:

  • The file has been overwritten by another file (so no need to overwrite this again)
  • The file had been overwritten by another file before you ran CCleaner, but the second file has now been deleted as well.
  • The file was created almost exactly when you ran CCleaner.