[Galaxy S III Q&A, Help & Troubleshooting] xs4all:
Hi all,

Thought I give my experience.

I am on my 3rd Sandisk 64GB microSDXC (Class 10 - UHS 1)!

The first two cards got corrupted after copying:

Card 1: Copied over 17gig worth of files, card stopped responding.

Card 2: Copied over 22gig worth of files, again card stopped responding.

GS3 would not format the card and even on the computer wouldn't format the card, after a few moments trying to format, error message says unable to format card.

Twice in a row? Surely...

Then I thought I must have gotten fake cards? I raised with the seller, he assured me he sold heaps without issues and would talk to his suppliers.

It turns out the last batch of cards he received was faulty, he tested the 4 brand new cards he had left in stock, 2 was faulty (same issues that I had) and the other 2 was fine. I agreed for him to send me the tested and working card.

After two weeks of stuffing around, I received my 3rd card tonight, put the card on my GS3, let the phone format to exFat.

Removed SD card and connected it back to my computer and started copying files.

Copied 10gig worth of data, totalling 10,557 files, able to see on computer, stick it in my GS3, all is well, can see all files, working fine.

SD card back into my computer and copied more files, this time copied over 24gig worth of files, totalling 8,800 files.

Now I have total: 19,357 files, Computer can see it all without issues.

Stick the SD back into my GS3, after scanning, the phone says Blank SD or Unsupported filesystem?

After reading through all the pages on this topic, it looks like our GS3 using exFAT on 64gig cards can't read "X" amount of files on the SD card.

I have about max 4 subfolders deep, so somewhere between 10,557 and 19,357 files, the SG3 has trouble reading and spits the error message.

I've tried to format the SD to Fat32 with no luck, tried a few tools error message says card is write protected? which it's not.

I can only format exFat on both the computer and on the phone.

I still have the original Galaxy Tab at home, so I thought I stick the card in there to see if I can format and what type.

The Tab threw the same error message but I was able to format the card, and what do you know, the good old Tab format the card using FAT32 :)

Put the SD back into the GS3 and the phone was able to see the SD card, I'm in the process of copying the same amount of files back onto the card to see how I go.

I'm on rooted stock vodafone (Australia) firmware: I9300TDUALF2

As someone posted, it doesn't seem like the exFAT is fully supported.

For those of you who are using 64gig card and exFAT, regardless if you have "X" amount of gigs on the card, try copying heaps of little files and see if the GS3 has issues scanning the card.

Will update soon.

*** UPDATE ***

All Good, SD card is Fat32, has 19,609 files total: 34gigs.

My MAME4Droid Reloaded rom folder with 8,800 files can also been seen in the emulator and ES File Explorer.

GS3 can see all files without any issues.

I can conclude for my situation, Fat32 fixed my issue :)

I hardly ever have movies on my sd card so the 4gig size limit wont affect me as I use the "Nearby devices" in the Video Player app to connect to my media share to stream movies.