my galaxy S5 tells me that my microSDXC card is not compatible

[AC Question]

it was fine until one day it notified me that apps were updated and all of a sudden the card was incompatible

 

[Rukbat]

About the only thing that can cause that (it should be "compatible" with cards up to 2TB, which won't be made for at least a few years) would be that the card went bad.

 

[B. Diddy]

Welcome to Android Central! I agree with Rukbat. Go to Settings>Storage, Unmount the card, remove it, and insert it into your computer. Can the computer read these files? Backup as much as you can right now, then run chkdsk to look for bad sectors: http://forums.androidcentral.com/am...guide-using-chkdsk-fix-corrupted-sd-card.html.