StarReminder has a complete backup mechanism. All backups are stored in "StarReminder\Backup" folder.
Every day on startup a backup of your database is created in the form "StarReminder.dat.DD-MM-YYYY". The backups of the last six (6) days are preserved. Additionally, a backup file ("StarReminder-001.dat") is created every one (1) hour.
Still for maximum protection you can create a backup anytime. From the Main window menu choose "File > Create a backup".