Hi there,

I assume you're referring to a project/session? There isn't really a dedicated "close" option, as it isn't really needed in most practical scenarios. Naturally, when you're shutting down the program, Cleaning Lab will make sure the project file you're working on is closed. Also, since Cleaning Lab is a single-document application, opening a new project or loading a different project via the appropriate options in the "File" menu will result in the current project being closed. If you're talking about a the file being opened for reading or writing access in a stricter technical sense on the operating system level, I don't think the project file would even be open outside of the "load" and "save" operations.