Hi when trying a simple collection.insert({ owner: Meteor.userId(), length:3 }); in Meteor it's executed by client but revoked by server (or in process, same for collection.update) At the moment I renamed the field length to 'len' and voila it works... But now I'm not in compliance with the GridFS spec saying: 'fs.files.length' (the project: collectionfs.meteor.com)