I jot got brand new Galaxy Tab A 10.1 tablet (580 model running Android 6). After using Odin 3.12.1 to install TWRP 3.0.2-0 custom recovery I tried to do a full image backup and it failed with "can't mount /data (Invalid argument). So I Googled around and found the "[SOLVED] Cant mount /data" video https://youtu.be/X7yDPszoQ5s that suggested to change data partition type from ext4 to exFat. After that the tablet does not boot and gives some criptic error about data encryption and dropping devices. Nothing, even factory reset helps. I read that Samsung does some encryption but I am not Android expert. Can someone help?