The Restore Previous and Backup History menus are in-app options used to recover exam work from a backup in the event of loss. These menus are designed to be a quick-access method of restoring work in an immediate exam situation, such as after a sudden crash or inadvertent closure of the software mid-exam.
To support this, the menus will only show recently saved backups (by default, the last 60 minutes of backups at time of viewing the menu); this ensures the list of options does not become cluttered and allows exams officers, invigilators or students to quickly locate the correct backup for their work and resume their exam promptly.
Backups saved outside of this recent period are not lost or removed, they are just not shown in the menu. They can still be recovered manually in Windows via the directory the backups are saved to.
For more information on recovering a backup, both via the menus and via Windows, please see this article.
The amount of backups shown in the Restore Previous and Backup History can be increased by adjusting the 'PreviousVersionsRecoveryMinutesDisplay' option in the Exam Settings (JSON) file, which controls the recent time period to show backups from, up to a maximum of 24 hours.
We would recommend keeping this period as low as you are comfortable with to minimise delays in finding the correct backup in these menus. This best supports their intention to be useful in immediate recovery situations, whilst the manual method in Windows will always be available to restore older work.