Reset database clears the metadata for your camera roll backup. For example, if you backed up your camera roll to Amber and for whatever reason deleted those photos on Amber and want to backup again, you're going to have to Reset database.
1. Tap the menu icon on the top left.
2. Tap the settings icon on the top.
3. Tap Auto Backup.
4. Tap Reset database.
5. Tap Reset database.
6. Tap Yes to confirm.