Scanning files for inappropriate content during synchronization

The present invention extends to methods, systems, and computer program products for scanning files for inappropriate content during file synchronization. Embodiments of the invention are mindful of the order of operations when scanning files for inappropriate content and in subsequent file processing. In some embodiments, during synchronization, an intermediary server scans a file for inappropriate content. The file is not permitted to be fully downloaded to a client device until the scan determines that the file does not contain inappropriate content. In other embodiments, during synchronization, a client device scans a newer version of a file for inappropriate content. An older version of the file is not deleted until the scan determines that the newer version of the file does not contain inappropriate content. In further embodiments, server side scanning and client side scanning are both used to enhance capabilities for detecting inappropriate content.