Synced cloud files are copies stored both online and on your device, actively kept identical via constant communication between the device and the cloud service. Any change you make on one side automatically updates the other. Unsynced cloud files exist only online, within the cloud storage itself; they don't automatically download a copy to your device unless you explicitly choose to open or download them. The key difference is automatic duplication and real-time updating versus purely online storage requiring manual action to access locally.

Synced files are ideal for actively used documents needing access everywhere, like updating a report on your laptop and instantly having the latest version on your phone via services like Dropbox, Google Drive, or Microsoft OneDrive. Unsynced storage is better for large archives, backups, or infrequently accessed files you want to save space on devices – think uploading years of photos to cloud storage but only viewing them through the browser or app without permanently storing them all on every phone.

The main advantage of syncing is convenience and seamless offline access to your latest files. Its limitation is consuming significant device storage and bandwidth. Unsynced files maximize cloud storage and save local space but require an internet connection for access and involve manual steps to work locally. Sync drives collaboration and constant access but unsynced is crucial for managing massive data volumes efficiently.