You can 100% do automatic nightly backups to an external drive in Windows without OneDrive, but you’ll want to use the right built-in tool (or a simple scheduled copy)
File History does not only back up files you’ve opened. It automatically backs up what’s inside your Libraries (Documents, Pictures, Videos, Music, etc.) plus common user folders, but anything outside those locations won’t be included unless you add it to a Library.
Do this:
- Plug in the external drive.
- Open Control Panel > search File History > Select drive > pick your external drive > Turn on.
- If your files are scattered across other folders/drives:
- In File Explorer, right-click the folder > Show more options > Include in library (or create a new Library), so File History will back it up.
- In File History > Advanced settings, set frequency and retention as you like.