Is it safe to delete the System Volume Information folder

OK. I can confirm that a user can delete a file (or remove an empty directory) without having write access to that file/directory if they have Delete Child access to the parent directory. If I was aware of this before, I had forgotten about it, but it is documented behaviour, e.g., see KB101651.

There are (at least) three ways to solve your problem:

• Give the users Modify access instead of Full Control access to the parent directory. The only differences between Full Control and Modify are the Delete Child right (allowing the user to delete child objects) and the Write DAC right (allowing the user to change the permissions on the object, even if they are not the owner).

• Set the permissions on the share to Modify instead of Full. This should have the same effect, but will only affect network users, not interactive users. One side-effect is that the users cannot change permissions, even on their own files.

• Set the read-only flag on the child file/directory. The documentation is unclear on this point, but my testing (Windows 7) indicates that Delete Child does not allow you to delete files or remove directories with the read-only flag set. It also does not allow you to reset the read-only flag. Note that the Explorer GUI implies that the read-only flag has no effect on directories; in fact it prevents the directory from being removed. (It does not prevent new files from being written to the directory.) Addendum: the read-only flag does not prevent a directory from being moved.

Other notes:

• You could explicitly deny the Delete Child right to the parent directory, but if the user has Full Control to the parent directory they could remove the deny entry.

• Having Delete Child right on the parent directory does not allow users to delete files from the child directory or to remove the child directory unless it is empty. Addendum: it does allow users to move the child directory.

Source Five hard disk cleaning and erasing tools

Brien Posey lists five tools that ensure your personal information is securely removed from all hard disks.

When it comes to disposing of old hard drives, simply erasing your files or reformatting the drive alone is not enough to ensure your privacy. In this age of rampant ID theft, it is more important than ever to ensure that your personal information is securely removed from all hard disks. That being the case, I decided to create a list of five utilities for securely erasing and formatting old hard drives.

Active@Kill Disk - Hard Drive Eraser

Active@ Kill Disk - Hard Drive Eraser is a free utility for securely erasing a hard drive. More importantly, this utility adheres to United States Department of Defense standards (DoD 5220.22M) for hard disk data removal.

Although some might consider it to be hokey, I especially liked the certificate feature. When a hard disk has been erased, the software generates a certificate that you can print as a way of proving that the disk has been securely erased.

Eraser

Eraser from Heidi Computers, is another free utility for securely erasing data from a hard disk. The most interesting thing about this utility is that it provides several different methods for overwriting data, based on a number of different standards. You can even define your own method for overwriting data.

This utility allows you to securely erase specific files, folders, unused disk space, or even the recycle bin. Furthermore, erase operations can be run manually or scheduled.

Shredit for Windows

Shredit for Windows is a privacy application that is designed to securely erase individual files, free space, or entire hard drives. The software lets you pick the write pattern and the number of writes. A number of different government standards are supported.

Shredit for Windows costs $24.95 for the download version or $34.95 for the CD-ROM version.

Disk Wipe

Disk Wipe is a free utility for wiping data from a hard disk in a secure manner. Like Eraser, Disk Wipe includes a number of different algorithms, including DoD 5220-22.M, and Peter Guttman. The really nice thing about this utility is that it is portable, so you don't have to install it to be able to use it. Furthermore, Disk Wipe works on more than just hard drives. It can also be used to securely wipe USB flash drives and SD cards.

Darik's Boot and Nuke

Darik's Boot and Nuke is a free, open source utility for securely erasing hard drives. Although this utility is designed to be secure and effective, the author does not explicitly guarantee that data is completely unrecoverable and there is no support for this application.

The article includes some screenshots of each tool.