Likewise, if you attempt to copy a placeholder file via the Finder from one volume to another, the agent software downloads the data to the source, then copies the original file (leaving the downloaded source file in place). Placeholder files may be backed up, but may not function as placeholder files on the backup diskĪs noted above, when you open a placeholder file in the Finder, the agent software downloads the original. Before using these online-only features, you should consider whether you are comfortable with not having a local backup of the files that you choose to store only in the cloud. While this is a convenient feature that allows you to free up some space on your Mac, this feature removes files from your local storage, which means that CCC can't make a backup of these online-only files. If you attempt to open the placeholder file, the agent software for your storage service provider automatically downloads the data of the file to your Mac and the document opens. When you specify that a file stored by one of these storage services should reside only online, the local copy of your file is deleted from your Mac and replaced with a 0-byte placeholder file. When you choose to have these services store your files only online, do so with the understanding that it's not possible to maintain a local backup of those files. iCloud Drive's "Optimize Mac Storage" featureįiles that are only available online will typically have a "cloud" icon or badge in the Finder, e.g.Microsoft OneDrive's "Free up space" feature.Dropbox Professional's "Smart Sync" feature.Some services that currently offer this functionality include: Some cloud storage service providers offer services that allow you to sync a local folder to "the cloud", and optionally choose to store those files only online, thus freeing up space on your hard drive.