If you save notebooks to Onedrive (default option in latest versions) you can install the Onedrive app and have it sync the documents folder to your machine all

If you save notebooks to Onedrive (default option in latest versions) you can install the Onedrive app and have it sync the documents folder to your machine all the time so you will have a copy on Onedrive, and your machine. Onedrive also backs up your data though you might have to go through Customer support to get to that.