Hey guys
My phone has the exact same problem.
So I got my first phone (Samsung galaxy S7 edge, 32gb) from T-mobile in June. I used to get the error message and an update prevented the error message from popping up but my memory card would keep getting "corrupted" and then after a few weeks, it would be fine. It happened three times and I let it be (twice it started working by itself and another time, I had to remove the card and reseat it). The fourth time it happened, I took it to T-mobile (on 11/26/2016). The manager there checked out the phone and the card and determined it was the phone (phone was made in Vietnam). He put in a warranty replacement and got me a new phone which I got last night.
I put in the same sd card I used in the old phone (Sandisk, 64gb), formatted it, transferred pictures onto it and it worked fine). Today morning, less than 24 hrs later, the same trouble has started. The pictures appeared as a broken file in the gallery and then, in restarting my phone, it disappeared from my gallery. SD card works fine though (I put it in another phone (HTC One E8) and everything appears fine on that phone.). I downloaded phone info and this phone is also made in Vietnam (date 2016.03.14). This issue is beginning to get in my nerves now. The phone is fully paid off for and I can't seem to get them to get me an iPhone even if I'm willing to pay extra.
Any help guys? What do you suggest?
Regards,
Vipin