As suggested in FileField Sources., in some cases it's necessary to disable the upload widget in file fields—for example, to force users to upload using a certain content type and just reference files from a different content type. This module allows just that. It's still a bit rough around the edges, but it works. Requires
Drupal 7 version
The 7.x version of this module won't be developed any further, as its functionality has been added to FileField Sources:.