Question Issues transferring files to MicroSD card

Mar 23, 2022
I'm trying to transfer a bunch of files (comics, books) to a card for use in my Android tablet and something's going wonky on the Windows side.
I'm using a Sandisk 512gb card formatted for exFat and when I drag all the folders and files onto the card plugged into my Surface Pro, everything seems to go fine with no error messages. BUT when I open the various folders on the card, almost all of them are empty. If I then manually drag and drop the files into the empty folders they transfer over fine, but if I shut the Surface off and restart and check the folders, the manually transferred files (which were there) are now gone again.

I've tried two different cards (both Sandisk) from two different suppliers on several PCs and the issue is the same. I've tried formatting multiple times with different allocation units and nothing's resolved the issue. I've had no problems with a similar Sandisk 256gb card.

The issue doesn't occur when it's formatted in NTFS but then the Android tablet can't mount or read the card.

Any ideas? Thanks!!