I have a 64 GB micro, formatted as exFAT, that I had been using in my Android phone and want to repurpose it for Windows with a USB 3.0 card reader. I've tried working with it in a Transcend USB 3.0 card reader and another USB 3.0 card reader without success.
Windows keeps complaining the volume bitmap is corrupt, the drive is "dirty", and won't let me do anything with it other than read files. Chkdsk with /F says "Corruption was found while examining the volume bitmap", which I'm assuming is in that first 16 MBs at the beginning of the card, which I can't seem to delete. Every time the card is inserted into my PC, Windows tells me to scan it, but then I don't get any messages back unless I run chkdsk /F from a CMD window.
I put it back in my Android 6.0 phone and asked it to format the card. It says it did, but then when I look at the card after the format is done. everything is still there. I did not tell to format as internal storage since that will encrypt the card.
I've used the SDFormatter v5 from sdcard.org. It recognizes the card and capacity correctly and says it formated the card okay. But the card still shows folders and files from my phone, and the first 16 MB "unallocated" partition is still there.
I've tried using diskpart, deleting the 2nd partition so the whole card is unallocated, doing a "clean all" which did nothing but waste a couple hours. I have tried several other partition manager programs including Paragon HD MGR 15, to delete the 2nd partition where the bulk of the space is.
They all show me the 2nd large partition is deleted and I see a fully unallocated card. But when I eject and reinsert the card, it comes back with that 16 MB area at the very beginning still as "unallocated", then the 2nd larger partition and Windows wants to scan the card again.
Nothing I have tried will delete that 1st 16 MB area. It's a micro SD card so there's no lock switch and I'm not using it in a standard size adapter that has a write protect switch.
From what I've read, I think this is something to do with storing the info used to encrypt the card. I don't recall ever telling my phone to encrypt the card but I may have.
I just want to blow away everything on the card, whether or not it's encrypted, and have a clean, fresh card to reuse. At this point, Windows can read from the 7 or so gigabytes of files on the card, so I don't think it's actually encrypted, but refuses to write new files or let me erase files.
I'm surprised that SDFormatter utility from sdcard.org claims it worked fine but that 16 MB partition is still there and the card can only be read from and not written to in Windows. That is supposed be THE utility one should use to properly initialize and format SD cards.
At this point, I'm stumped, so I'd welcome any ideas for totally wiping the card so I can use it again.
TIA,
Mark
Best Answer
I had a similar problem with a Samsung EVO Plus SDXC 128 GB card, where I was puzzled that my changes to the file system disappeared after the card was removed from the drive. It turned out that the card was broken and I couldn't write to it although no error was reported when I edited files and their contents appeared changed. However once I removed the card or rebooted my Raspberry Pi nothing had changed.
So maybe your card is broken. I got mine replaced by Samsung for free.