Online-only files (placeholders)
Also known as: files on-demand, cloud placeholders, online-only, on-demand files
Online-only files (placeholders) show every cloud file on your device but store its contents in the cloud until you open it. The file appears in your folders and takes almost no disk space; it downloads on demand and can be made online-only again to reclaim space.
- All files visible; contents stay in the cloud until opened
- Placeholders use almost no local disk space
- Right-click "Free up space" to make files online-only
How placeholders work
With on-demand syncing, the client lists all your files locally but keeps most of their data in the cloud. Each placeholder holds just enough metadata to show the name, size, and icon. Opening one downloads the full file automatically; you keep working as normal.
On Windows this is OneDrive Files On-Demand, where a cloud icon means online-only and a green check means a local copy is present. Dropbox calls it Smart Sync / online-only, and macOS shows the same idea for iCloud Drive and other providers.
Using it to save space
To reclaim disk space, right-click a file or folder and choose Free up space (OneDrive) or set it to Online-only (Dropbox). The local copy is removed while the file stays in the cloud and still appears in your folders.
Files marked Always keep on this device stay downloaded for offline use. Storage Sense on Windows can also turn rarely used files back into online-only automatically when space runs low.