How do I fix failed to mount data?

INSTRUCTIONS :

1. Reboot your device into TWRP Recovery.
2. Go to Wipe menu.
3. Go to Advance Wipe.
4. Select Data and go to Repair or Change File System.
5. Click Repair File System. ( …
6. Go to Change File System.
7. Select Ext2 and swipe to confirm.
8. Now change back to Ext4 and swipe to confirm.