If Prism (or your computer) crashes or freezes, the backup files will remain on your hard drive. If Prism quits normally, the timed backup files are deleted. How automatic backup works: Prism Windows, and Prism Mac up to version 6
Choose automatic backups on the File & Printer tab of the Preferences dialog and Prism will automatically save your work every few minutes and/or when you flip from sheet to sheet (page to page).