I have a Moto G (3g) with Android 6. I noticed that When I go to Settings>Storage>Internal Storage, it shows that 2.85GB are being used out of 11.81GB. However, If I add up the storage shown for each category, the results are less than what is shown as total usage. This are the values shown:
Videos: 0.00 B
Audio: 0.00 B
I have used several tools (like Storage Space) and they all show the same.
I used DiskUsage and it shows a "System data" used storage, that fills in the gap.
I know Android has a system partition, but this "System data" is shown in the data partition.
Why does this happen? What is stored in "System Data"?