Share your experience!
I have this 16 GB SanDisk (4 HC) which was working fine on Android 5, but after upgrading to Marshmallow (6.0.1) it's not detected anymore, no matter how many times I remove it and reinsert it on my phone, and is not my SD since it is perfectly detected on my computer with an USB adaptor. I'm thinking it might be a problem with SanDisks cads since I'm inserting other branded cards and they are immediately detected, I don't know it any other SanDisk users can confirm this (using Android 6.0.1).
Solutions I tried:
1. At first I thought it was a bug in the installation so I tried to reinstall Android via PC Companion under the "Repair my phone" option, but it didn't helped at all.
2. I formatted my microSD card on the computer in Fat32 and NTFS, and it's still not detected on my phone.
I guess if I don't find a solution to this I'd need to get a new SD Card, because the other branded ones I mentioned are not mine so, thank you Sony.
Hi,
My phone also doesn't recognize my SD card since the update.
I don't have a lot of experience with SD cards and formatting. If I do what you did (create and format hard disk partitions), will it erase all data on my SD card? I have no idea what it means... 
Will this remove all data?