Files On-Demand is a feature in Windows OneDrive that lets you see all your files in OneDrive as they appear to be on your computer when they are actually stored in the cloud.
This allows you to save space on your hard drive by fetching a file only when you need it.
Files on-demand is available in Windows 10 version 1709 or later. Here is the official documentation from Microsoft.
You can control which folders you want to keep offline by right-clicking the folder and choose “Make available offline” or you can turn the feature off altogether in the OneDrive settings.
Here are some solid reasons why you might want to turn it off.
Files On-Demand = no access to files without internet connection
If you are offline (you never know…) you will still have access to your files.
Files On-Demand consuming more cellular data
You will conserve a lot of data if your internet subscription is on pay per gigabyte.
Files On-Demand does not work with file indexing
Windows 10 does not index files in OneDrive, unless they are physically present on your computer. This means you cannot search for a file in Start, unless you have turned off “Save space and download files as you use them“. At least if you have them on a separate drive.
Downloading large files with Files On-Demand is tedious
Large files, for example, ISOs or video files will take a long to download when you need them. This is annoying if you are in a hurry.
Files On-Demand keeps your files in the cloud only
Obviously… Files On-Demand does not store your files locally and therefore, you will never have a secondary backup option.
For example, if you decide to reinstall Windows, keeping your OneDrive files on a separate drive will allow you to do a clean install of Windows and not having to re-download all the files again. Although keeping the files offline will not constitute a backup, files offline may be recoverable with a tool such as Recuva if they are accidentally lost.
If your files are deleted or corrupted they may be recoverable due to OneDrives version history, but only for 30 days. If you had them offline you could extend that time frame by using Windows File History or a backup service such as Backblaze.
Files On-Demand makes file search slow
Searching files is considerably faster when the files are available on the drive. At least if you are using an M.2 drive or an SSD.
Files On-Demand might not be compatible with antivirus software
Files On-Demand might not be compatible with some third-party antivirus solutions or backup tools.
If you are a system administrator I would advise you to rethink your policies. Files on-demand might be useful for some, but it might be wise to leave the feature optional.
If you are a private customer, you don’t need files on-demand unless you really have storage limitations, which is hard to imagine these days 😂