In Duplicate File Detective, a project is comprised of all the attributes that define the current duplicate file search. These attributes include the current filter criteria (such as file name masks, etc.), search paths, exclusion folders, file matching methods, visible duplicate result report columns, and more.
One of Duplicate File Detective's most powerful features is its ability to save and load projects as needed. Duplicate File Detective does this with project files, which have a file name extension of .dfd (e.g. "my-dup-project.dfd"). Double-clicking a project file in Windows Explorer will trigger Duplicate File Detective to load the project.
For more information, see the Managing Projects section of this help file.