I brought a new micro SD 32GB (sandisk) and soon I put into my Lumia 640XL.
First thing that I tried was move the apps to card, but everything goes wrong and I had to reset my phone.
Later I put the card into my PC to copy some mp3, I take it off (safe) and put into the phone. Nothing happens was like the card was empty.
I go back the SD into the PC and I found a lot of folders named UUUUUUUU.uuu
What is that? A virus? I search on about it, but nothing worth that have fix the problem.