You can download HDD Safeguard 3.0 from our software library for free. HDD Safeguard lies within Security Tools, more precisely Privacy. This tool was originally developed by USB Safeguard, Soft.
From the developer:
HDD Safeguard is a portable software that allows you to protect your private files with a password on your external big drive using the secure AES 256 bits key. It protects data with a password for the entire portable storage device (HDD hard drive, USB flash drive, SSD, etc.) and not just for an virtual partition. Once the drive is locked, one cannot read nor write any data to it without the correct password!
You may want to check out more software, such as BitRecover Parallels HDD Recovery Wizard, SP HDD Lock Utility or HDD Unlock Wizard, which might be similar to HDD Safeguard.