The “Delete locked or inaccessible item” feature is designed to easily delete files and folders that are locked,
cannot be moved to the Trash, or are owned by other users. If the “Use secure delete” option is selected in
the Preferences, this feature can also be used to securely delete any items by dragging them to the drop zone in
the drawer.
It is very important to remember that this feature does not remove aliases and symbolic links but the files and
folders referenced by the aliases and links. Misuse may result in accidental data loss. If you cannot delete the
items using Cocktail, it may be a sign of serious directory damage. Start up your computer from the macOS
Recovery HD and use Disk Utility to verify and, if necessary, repair your disk.
When dropping item on the drop zone in the drawer Cocktail will always prompt for a confirmation when deleting locked files.
If used in a improper way the remove locked files feature can result in data loss. It is important to not use this powerful
feature without care. There exist third party tools which can be used to try to regain data. Examples of tools to recreate
deleted files are DataRescue from Prosoft Engineering and VirutalLab from BinaryBiz.
The SRM secure delete removes each file by overwriting, renaming, and truncating it before unlink-ing. This option meets the US Department of Defense (DOD) 5220-22M standard for securely erasing magnetic media. It erases the information used to access your files and writes over the data 7 times.