Back up just saved a page of work for me.
I am using EX story mode. Have about 50 pages of thumbnails, and when I tried to change the resolution to something higher to start doing tight pencils and inks, one page disappeared. I got a message that something was wrong with page 26 (which is page 2) and it would be replaced with a blank page.
Luckily I use w10 backup and was able to retrieve the files from the previous day. Then I could pull the missing page and replace the new blank page with the thumbnailed page.
Not sure what went wrong, but glad my backup works. (I also keep working projects in the cloud, and another back up on a nas. Can't be too careful folks).