To delete a file or folder, you can either:

By default, Opus deletes files to the recycle bin when possible. Files that are deleted to the recycle bin can normally be recovered (via the Undo command), until the recycle bin is emptied. The recycle bin is not supported on network drives or removable media, and files deleted from inside archives or on FTP sites also can not be recovered.

If you hold the Shift key down when pressing Del or clicking the toolbar button, you can bypass the recycle binĀ and permanently delete the file.

The drop-down menu attached to the Delete button on the default toolbar contains several commands and options relating to deleting files:

Delete menu

Delete options

The File Operations / Deleting Files Preferences page contains several options that let you configure the Delete function in Opus. You can choose whether Opus asks you for confirmation before the delete (you can even have it ask you before each file if you like), and the use of the recycle bin can be configured. You can also choose whether files marked as read-only can be deleted without a special confirmation prompt.

More: Secure Delete