On Windows 11 and Windows 10, BackupOnShutdown can store a backup on an external drive, a USB stick, or a NAS folder the PC can already open. One backup can use several locations, which the app writes to one after another. Every folder you selected is copied to each location that is connected when the backup runs.
Which locations can you use?
A local folder works, and so does a USB stick or external drive that shows up in File Explorer, or a network share the PC can open like any other folder. A mapped drive letter and a path such as \\server\share are both accepted when your Windows account can write there. BackupOnShutdown doesn't sign in to a NAS or a cloud service, so connect the share in Windows first, then open the folder in File Explorer and check that you can create a folder in it. A NAS name in the network list is not proof of that.
Leave room for your files and for older versions. How long those versions stay is one setting for every backup, described in how long old versions are kept. The app manages the backup folder, so don't rearrange its contents by hand. An empty folder is used as it is. If it already contains other files, those files stay, and the backup goes into a new folder named BackupOnShutdown, then a folder with the backup's name. The app shows that path before you continue. If a backup is already kept there, pick another place or open that backup.
You choose the first location while setting up your first backup.
Can you use a USB stick?
Yes. A USB stick is a valid place when Windows shows it as a drive you can write to. Plug it in before you start, choose a folder on it, and leave it connected until the run finishes.
A USB stick can work well for documents. For large photo or video libraries, choose an external drive with room for your files and older versions.
After a successful backup, unplug the stick and keep it away from the running PC, so a problem on that PC, including malware, can't reach this copy at the same time. Plug it in again the next time you back up. Flash memory wears out, so restore a file now and then, and replace a stick that reports errors.
Why use a different drive?
Another folder on the same drive doesn't survive that drive failing. The warning reads "This is the same drive as your files. If the drive fails, you lose both." An external drive also has to be connected when you run the backup.
The backup location can't sit inside a folder the same backup includes, or it would try to contain its own output. The app stops that with "The backup can't be kept inside a folder it backs up. Choose another place." Pick a place outside the selected folders, preferably on another drive. Putting the backup inside Documents while Documents is being backed up doesn't get fixed by renaming the backup.
How do you add several locations?
Open the backup and find "Backup location". "Add location…" adds another drive or folder, so the same backup can go to an external drive, a USB stick, and a NAS. The locations are written one after another, and each one has to be reachable when its turn comes. Use "Add another backup" when you need a different list of folders.
Check the path, especially when two external drives have similar names. Removing a location from the app stops future backups from going there. It doesn't delete files already saved there, so note the path if you still need those versions.
If the folder already holds a backup that was made with a different password, the password guide explains the three choices. Read the options carefully before deciding whether to keep or erase the existing versions.
What if a drive is unplugged?
If the backup can't reach any of its locations, BackupOnShutdown stops before the run and shows "Backup drive is not plugged in". Connect the drive and choose "Try again", or cancel. The PC stays on, because the backup has not started. In the backup's details, a missing location is marked "Not plugged in".
When several locations are set up and only one is missing, that one is skipped and the others still run. The summary marks it as not plugged in and skipped. Reconnect the missing drive and run again to update that copy. Skipping an extra location doesn't, by itself, stop Back up & shut down from turning the PC off. A drive that is plugged in but fails is different, and the PC stays on.
Can you sync the backup folder to the cloud?
BackupOnShutdown doesn't provide a cloud backup. It writes only to the folder you chose, so don't point a sync program at that folder. A sync can upload or change part of the folder while the backup is still writing, and the other copy can end up incomplete.
For a second copy, add another location and let the app write it. Files you want backed up from a synced folder also have to be present on the PC. A placeholder that downloads only when you open it is not the file.
Download BackupOnShutdown and try a backup onto a drive you can unplug. The trial is 14 days, with no account and no card.