I bought a Sandisk 64gb MicroSD, which came formatted in exFat. I could see this partition in both Windows 8 and Linux on my laptop, using an SD card adapter (plugged into the SD card slot).
I wanted to reformat it to FAT so that I could use it in my Cowon mp3 player and/or old phones, so I booted into Linux Mint and ran Gparted. I formatted to FAT leaving 32mb front and back (which I read was necessary to make sure Windows sees it), and in Linux all was well. I copied some files over, put it in the Cowon and it worked.
But... it no longer shows up in Windows. Neither while it's in the device (over USB), or when I put it directly in the laptop in the SD card slot.
I have tried using Gparted to re-partition the drive and reformat using a number of different options - including having no partition, a small FAT or NTFS partition etc, and nothing works. In Windows, not only does it not show up as a partition, but it can't even see it as a drive - Disk Manager doesn't show it, and neither does EaseUS.
I have also had the same problem with another MicroSD card, using the same steps - works in Linux and on the the device - Windows no longer thinks it exists.
Help much appreciated!