Originally Posted by Mittens
I had the almost identical things happen to me. I used a micro sd card adapter to read the files on my pc. I never tried using the USB connector.
Yeah, the first couple times I also used an adapter and card reader to like copy my 20 Gb of music files to it and a few other things. So now I've reformatted the card a 4th time from the phone and purely used the USB cable with the phone to transfer stuff. It went about a week stable, but then last time I powered off and back on my phone, sure enough, when it powered up I got the message that my card had an issue and wanted me to reformat it again. I didn't, and just went into Settings/Storage and mounted the card. It mounted but I still couldn't see any files on it. So I unmounted and mounted it again and then I could see the files. I haven't power cycled the phone again yet since then (about 2 days ago).