Do you have a Windows machine to hand? If so, pop your SD card into the Windows machine and run a Check Disk on it using the command prompt. You'll need to find out the drive letter assigned to your card, but Windows'll probably pop up asking you to format the card when you stick it in.
The command you'll need is chkdsk [drive letter of card] /f /r.
It's been a while since I've tried that fix, but it always worked when I was using a MicroUSB adapter to attach an SD card to my Galaxy S6 😉. Hopefully that work for you too 🙂.
In terms of the format used, cards under 32GB use FAT32, and cards over 32GB use exFAT.
Hi there infobleep my understanding is the following...... Cards above 64 GB are formatted to exFAT file system. If you are formatting your SD for your Android phone or Nintendo DS or 3DS, you will have to format to FAT32. ... Formatting to FAT32 is usually your best option, however, FAT32 formatted cards won't let you transfer or store a file more than 4GB.
Good to hear best practice of you having backups in Google photo/Other storage in case of the dredded corrupted sd scenario.
Usually I moan about Windows not being that good but in this case I have got the issue down to 2 photos that didn't copy wen corrupted.those two files of 0kb are that was stopping the cards being read!
Once the data is off I will format the card. I assume its best to do this on my phone, prior to doing anything else further. The data will be put back using my computer and in future I'll be doing a lot of taking out of the card from my mobile, to write data to it.