SubRosaSoft, meanwhile, has released the first edition of FileDefense, a security program which operates at the file access layer. Rather than scan and delete malware, the software blocks any and all file access by unauthorized programs. Its security is said to be so strict that users must temporarily disable it to install new programs; once this is done, users can drag-and-drop icons into the FileDefense window to expand authorization, or simply click "Allow" when a program attempts access. A number of apps are pre-listed in the FileDefense database. The software supports both Tiger and Leopard, and is a $60 download.