PSA RE: SanDisk 32GB/64GB MicroSDXC Class 10 UHS-I
IF OWN THIS SANDISK 32GB OR 64GB C10 UHS-I AND YOU ARE HAVING ISSUES WITH THIS CARD
OR IF YOU WANT TO RECLAIM YOUR 16MB BACK SEE THIS POST!
This applies to the SanDisk Mobile Ultra 30MB/s 32GB or 64GB Class 10 UHS-I cards (the Class 6 cards did not have this issue (I believe)
To everyone - you may have a problem with this SanDisk C10 card in your Android device (especially the Galaxy 7.7 and S2).
Not because its C10, not because its UHS-I, but because of SanDisk's making 2 partitions.
edit: it may be that both the 32GB and 64GB C10 cards both have 2 partitions. you may have to do this for the 32GB C10 card also.
The old 64GB C6 card just had 1 partition, one large 59.48GB (after format) drive
After further inspection of the C10 card, I found out that SanDisk stupidly added in an offset of 16MB at the beginning of the card
(which might house that weird secure stuff that SanDisk has, but not necessary).
I'll post up a screen shot (and a formal thread of this problem later)
Basically, in order to get rid of it: (in Windows)
- Press Start
- type "partition", and the link "Create and format hard disk partitions" should pop up
(alternatively, you can just type diskmgmt.msc)
Disk Management will load up at this point. You should see a list of all the drives you have.
- Find your 64GB MicroSDXC. You should see that it's divided into 2 sections, one 16MB "empty" partition, and one 59.45GB exFAT partition
- Normally you could just Right Click on the partition and delete the partition to combine the empty space, but Disk Management won't let you do it in this case.
Now, in order to format your drive so it's 1 whole piece:
- Go to start, type in cmd
- Right click on cmd, and select "run as Administrator"
- command line will start w/ Admin privileges
Here, you need to run a program called DiskPart. It helps you "clean" hard drives that have many partitions that aren't normally accessible.
- from cmd line, type diskpart
- a new command line program will start
- here, type "list", it will show you a list of commands.
- type "list disk", find out which disk is your 64GB micro (mine happens to be disk 8)
- type "select disk #" (# is your disk you want for cleaning)
- disk # will be selected.
Very important: Make sure you have the right disk!
- If you are sure, type in the word "clean". This will completely wipe out the disk that was selected.
after that, you're done, you can exit DiskPart/cmd.
Go back to Disk Management, and now you can see that the whole drive is unallocated.
At this point, you can format your drive (using your Android device or Windows, to FAT32 or exFAT) and it will use up all the space (59.45GB + 16MB = 59.47GB?, lol)
I formatted mine to FAT32 because from what I've read and experienced with my other devices, it's just safer that way. I've had issues right off the bat using exFAT on some devices (mostly Samsung) or gradually the card will become corrupted (I've lost about 3 full microsd cards full of data so far). From what I've read this is due to Samsung using a half baked implementation of exFAT. exFAT is a patent-pending, proprietary file system created by Microsoft, so if Samsung, or any other OEM wanted to use the full implementation they would have to pay licensing fees. So while you can format it to exFAT using a PC, the way Samsung devices handle it there is high chance of it getting corrupted.
