Examples are related to systems and methods for controlling access to document files on a document server. One example system includes document files stored on a document server, at least one of the document files referencing a file lock, and a document access processing module. The example document access processing module includes a file sharing processing module that determines a coauthoring status of a software application of a client computer requesting access to the document file, and a file lock processing module that stores one or more file locks and that controls the setting and resetting of file locks. The example document access processing module uses the coauthoring status of the software application and the file lock status of a document file to determine whether a software application is permitted to have write access to the document file.