[AC Question]

My HTC One SV came with a 4gb microSDHC card. It would occasionally stop recognizing the card it came with, but this was always fixed by just turning off the phone, removing the card, reinserting it, and powering the phone back on. I recently purchased a 64gb microSDxC card. After inserting the new card into my phone, the message "Damaged SD Card" pops up at the top of my phone. It tells me to try reformatting. I've tried formatting from the phone as suggested, to no avail. The card won't mount. I've inserted the card into my computer, and tried with it formatted it as exFAT (the only options are this and NTFS). After formatting from my computer, I'm able to move files to and from the card and open them without issue. Once the card goes into my phone, the same error message appears, and I cannot mount the card.

[srkmagnus]

Does the car mount on other phones or devices? It could still be damaged, or you have damaged hardware that reads the SD cards.

[Rukbat]

Even assuming that there's no problem with the phone, it can only handle up to 32GB cards. It can't see a 64GB card. And, as srkmagnus said, the SD port could be intermittent, which is what caused the problem with the 4GB card. (Or the card could have been intermittent.)