Share your experience!
Dear Sir
I have Some Problems in my sony xperia c3 dual
First
Storage Bug
as shown in images free Space in internal memory different from pc and phone
Second Problem
GPS Bug
gps didn't Getting lock
it only show my position in 30 or 50 meter and there is no realtime navigation
i tried to purge agps , reset to factory settings and repair it with sony pc companion change between gps modes " high accurcy , mobile data and wifi only , gps device only " but its useless
Please note that all those problems happened when i updated my device from kitkat to lollipop 5.1.1
so,
if you can release an update fix for those problems i would be thankful
sorry for my bad english 
Best Regards ,
About your first question, this is how your PC will reserve memory when you connect the device:
/t5/Software-Updates/Can-t-update-to-5-1-1-on-T2-ultra-because-my-PC-shows-0MB-of/m-p/1035890#M26021
There is already a topic about GPS:
/t5/Xperia-C3/Gps-not-working-after-Lollipop-c3-dual/td-p/1055960/page/2
Have you tried the suggestions there?
In this case, we can't help you here. It is best if you visit a service centre and let them examine your device.