Data Shredder - Shred free space

Manage these settings from: ☰ Menu ▸ Settings ▸ Data Shredder ▸ Customize ▸ Shred free space

The Shred free space screen allows you to specify which method Data Shredder uses to shred the remains of previously deleted files. After making any changes, click OK to save Data Shredder settings.

Note: Data Shredder is available in Avast Ultimate and Avast Premier only.

Manage Algorithm settings

Under Algorithm settings, click the drop-down menu to expand the related settings and select your preferred overwriting method:

  • Random overwrite: overwrites your data with random patterns. The number of times your data is overwritten is determined by the number you specify. Click the text box and type a number of passes (the default number is 1). This is the simplest and quickest method.
  • DOD (Department of Defense) 5220.22-M algorithm: overwrites your data with several types of data (0, 1 and random characters) within three passes. This method is more secure, but slightly slower than the Random overwrite method.
  • Gutmann method: overwrites your data according to the encoding mechanism used by the drive. The Gutmann method performs the largest number of passes over the data in comparison with other methods. This is the slowest, but the most secure method.

Configure other options

Under Options, you can specify which areas of file information to shred:

  • Clean free disk space: erases free disk space that remains after deleting the files in a regular way.
  • Clean cluster tips: erases "gaps" in space which has been overwritten but can still contain data.
  • Clean MFT (on NTFS): erases Master File Tables (MFT) entries that contain file reference information (file size, date stamps, permissions, etc.) from the data structure for NTFS disks.
  • Clean FAT directory entries: erases file reference information from the data structure for FAT disks.

By default, all options are ticked to ensure that each information that can help identify a file will be permanently erased.