Kefir has implemented checks to prevent data manipulation. Frequently swapping manual save files can lead to account flags or "Server Connection Error" loops, as the server detects a discrepancy between your local timestamp and the cloud timestamp. Recovering a Lost Account
If you do not link your save data to a permanent external ID (Google Play Games, Apple Game Center, or an email), your progress is tied to a fragile local file that can be deleted by a cache cleaner. grim soul save data