A method and system for preventing duplicate file uploads in a remote content management system is described. The user device receives a hash value list associated with the files stored in the remote content management system. The user device calculates a hash value associated with new files to be uploaded. The system then compares the hash value(s) associated with the new file(s) to be uploaded with the hash value list received from the remote file storage system. If the hash values of any of the new files to be uploaded match a hash value on the hash value list, then the system prevents the new files from being uploaded to the remote file storage system.