- You accidentally deleted a card type or hundreds of cards and didn’t notice in time to undo it.
- Your collection has become corrupted.
- There was a syncing error and you accidentally overwrote a large number of reviews that you did on another device.
- …or anything else that leaves you with lost data.
- Restore a backup made by Anki on your computer
- Restore a backup made by AnkiMobile
- Restore a backup made by AnkiDroid