[Android Q&A, Help & Troubleshooting] dirtyballoonot:
So, this may be helpful with others that have had issues with Samsung, or other Android Phones and Sandisk microSD 64BG cards.

short version: if you have an issue go to support.sandisk.com and they will approve an RMA. If you want the details keep reading:

I got a 64GB microSD and tried to move the files from my PC to the card via the card reader and SDCard adapter.

I have an ATT SGSIII and a Samsung Galaxy S 4.

About half-way through I get "An unexpected error is keeping you from copying the file. If you continue to receive this error, you can use the error code to search for help with this problem."

Error 0x80070570: The file or directory is corrupted and unreadable.

[Description of file.mp4]

I searched high and low and found many users with this issue.

Many formatted as FAT and that worked, so, I tried that to no avail. Same error.

I tried low level format, recreating the card as FAT32, making it an active partition, 32KB, etc. Same error.

I tried formatting as exFAT in the phone and then transferring. No luck.

I tried non-windows copy utilites (Teracopy and FastCopy) that did transfer the files successfully, but when I put the card in the phone it said "Damaged SD Card"

So, I found this little nugget on Google:

"SanDisk has been made aware of potential product issues involving a very small percentage of its 32GB and 64GB SanDisk Mobile Ultra microSD cards. Under certain circumstances the cards may lock up and the card becomes inaccessible. The issue has been identified and a manufacturing fix has already been put in place. SanDisk stands behind its products and any customer who experiences this issue with the microSD cards cards is asked to contact the SanDisk support center for a resolution immediately."-SanDisk

I filled out a support request and they sent me back

Thanks for emailing SanDisk Technical Support. It is our goal to make sure you have all the resources you need to get the most from your product.

We understand that 64GB Class10 Ultra MicroSDHC I memory card fails to work on your Samsung Galaxy even after formatting on the computer. Since you have already referred to the link from our Knowledgebase, most likely this card is no longer functional and needs to be replaced.

Please backup all your important data and then format this memory card and provide us with the following information to create a possible replacement for your product.

- Your Phone number

- Your complete physical address (No P.O. Box please)

- What is exactly written on the face of the card?

- The Serial Number (Alpha Numeric Code ) written on the back of the Card

- From where did you purchase this product?

- Exact or approximate Date of Purchase of the card in the format of MM/DD/YYYY

- How was the product packaged at the time of purchase?

- Did the packaging have some other company name and logos on it?

- Are you getting the product replaced for the first time by SanDisk?

- In case of RMA, we need to share your name and address with our shipping provider, to create a pre paid shipping label for your use. Do you agree to this? (US customers only)

Please refer to your My SanDisk at http://kb.sandisk.com anytime to see all of your incident history and product registration information. You can log in using your email address as your login and the password that you created.

Also, you can visit http://kb.sandisk.com, our online keyword searchable Knowledgebase, to easily find answers to your Technical Support and Customer Service questions for all of SanDisk's products. Simply enter your search terms and our Knowledgebase will search an extensive database of commonly asked questions as well as our online forums at http://forums.sandisk.com to provide you with the most complete answers possible.

Best regards,

SanDisk Technical Support