Securely Delete Files

Before you proceed: These instructions are intended for users who manage their own computers. If your computer is managed by U-M, do not proceed. Contact your IT administrator for further assistance.
If you need to erase a U-M owned device, please see: Erase University-Owned Devices.

Why Securely Delete?

Electronic devices contain large amounts of personal information, and may contain also contain U-M data, depending on their use. When in doubt about what data was on the device or media, it's best to play it safe and treat it as though it contained sensitive information. This protects you, as well as U-M. 

In most cases, simply deleting data files is not enough to meet the obligation to protect university data from unauthorized disclosure. Depending on data type, various regulations and laws may require additional steps for disposal. In that case, follow the more stringent requirement.

Deleting Versus Secure Deleting

When a file is deleted from your computer, the only data erased from the hard drive is a small bit of information that points to the location of the file. The actual file remains on the hard drive, where it can be retrieved with common software tools.

A secure delete application or process prevents the recovery of deleted files by overwriting the file data with meaningless data. Securely erasing data with this procedure is considered a best practice for eliminating sensitive data, and it is a critical task to perform if you sell or give away your computer.

Securely Delete Files or Folders On a Windows PC

Heidi Eraser is the recommended application for performing a secure deletion of files or disks on a Microsoft platform. The application is free and can be downloaded from the Eraser Downloads Page. You should download the most recent build under the Stable Builds header. You need administrative rights to your computer to install the software. Please see the Eraser Forum for assistance with any questions you may have.

Securely Delete Files or Folders On a Mac

OS X provides built-in tools to help you securely delete files by using the Secure Empty Trash option, or the secure erase options in Disk Utility. See Apple's documentation for more details.