First,sorry about my english .
After i has updated 4.3,i lost all my data saved in internal storage.(Photos,videos etc)
But as u can see in the picture,almost 2.4GB data is disappeared .
There is a huge space in grey shown in the graph(which should be "available").BUT it didnt show in "available".
I was thinking if those data are still there but it is hid during the update.
I am looking to see if there is any solution for it.
EDIT:I used a apps called diskusage to do a check.
2.5GB stated as system data but all the firmware should be counted outside of the 5.5GB storage.(stated in sony website.)