Unlocker 64 bit is a System Utilities software developed by ccollomb. After our trial and test, the software is proved to be official, secure and free. Here is the official description for Unlocker 64 bit:

"Marydown.com is an Official Mirror of Unlocker installer."
BSEditor: It has many other flavors:

Cannot delete file: Access is denied
There has been a sharing violation.
The source or destination file may be in use.
The file is in use by another program or user.
Make sure the disk is not full or write-protected and that the file is not Currently in use.

Changelog for version 1.9.1:

- New feature: Made it possible to delete deep directory structures and too long path errors.
- Improved UI: Progress bar when deleting large Folders
- Improved UI: Fixed all references to previous website in UI

- Fixed Bug: Fix crash which happened with deep paths in old versions
- Fixed Bug: Fixed update check to match new Unlocker website (http://unlocker.emptyloop.com)
- Fixed Installer: Fixed x64 installer for references to non existing assistant

- Improved UI: Fixed same process appearing differently depending on cases.
- Promotional feature: Fully optional eBay ShortCuts, Bing or Quickstores toolbar depending on location.