SD Card showing up, but not working

[thugacation]

I have a S4, I bought a 64gb SD card, it seemed to be working fine, but the other day I attempted a nandroid back up which required approximated 2.8gb, which should be just fine, but it failed mid-way, telling me my SD card is out of space. This makes no sense as when I look at my storage through system settings it shows 56gb available, I then realised I was also unable to move apps2SD.
I formatted the SDcard the other day, using FAT32 and 32Kb file allocation.
Again it shows up fine in my system storage, but I'm unable to move apps to it.
Now when I tried a nandroid back up, it worked fine, but during the procedure, while checking how much storage I have, it says 7277MB of space, when the SD card is completely empty.

 

[mikedt]

Probably you got a counterfeit SD, there's a lot of them around. You can check it with this SD tester.
https://play.google.com/store/apps/details?id=air.com.anotherflexdev.sdcardtester.SDCardTester

 

[thugacation]

I've installed the app and run it, no issues, managed to deal with 5gb file, write/verify/read @ approx 30MB/s
I've been reading up on it, it seems possible that flashing roms created a emulated partition or something. That is something similar to what apps2sd says.