Originally Posted by hakam3akasheh
My card is Samsung 64 GB Class 10...
My card is exactly the same (I think) Samsung miniSDXC 64GB. Bought from a normal retailer. Similar problem to yours (I think)
I have not been able to find a solution.
The SD worked fine for a couple months. I notice there is no click upont pressing the card in (as the Sony manual describes) but it seems to sit a fair way in. Sometimes when viewed in Settings the card is visible but never when the phone is plugged into a USB port of the computer. Mostly it shows instantaneously when you push it in and then dissappears as quickly and the request to mount a card shows.
On one of the few times it stayed visible (not with the USB cable in) it showed about 12GB used. It seems to have been coming on and off intermitently during use. Accordingly, some photographs end up going to it and then not being accessible and some, or most, just end up in the main phone memory. This is assumed as a number of photographs taken are not showing. I have sent them from the phone main memory via dropbox as the computer can access none on the phone at all...perhaps because I have pathed them to the SD.
Will get and try another SD card but one possibilty is that this may be a problem with the SD card housing in the telephone.