Technology is disclosed for classification of data objects (e.g., files) in a distributed file system based on application creation and/or access information. In some embodiments, data objects of a user are stored across multiple computing devices associated with a user, e.g., mobile computing devices such as a tablet, a laptop, or a smartphone, and/or at server systems, e.g., cloud-based storage servers, in a distributed cloud-based storage system. The technology described tracks the applications that create or touch particular data objects in the distributed file system and classifies the data objects according to these applications resulting in various application classifications. For example, a classification engine can process data objects in the distributed file system to identify an application that created the data object and/or applications that have accessed the data object. The classification information can be saved by, for example, a cloud-based storage server.