Portable Storage vs Internal Storage in Android 6.0 Marshmallow

Differences: Motorola Support.

Card is encrypted and not accessible outside given device. Thus, for example, you can’t take it off, connect it to your computer and copy files that way, in case you couldn’t do this via USB cable (due to completely poor MTP protocol). For the same reason, if Android fail to recognise your SD card (happens awfully often under 6.0 Marshmallow) then you can’t access your files (i.e. download your pictures etc.) at all.

For security reasons (right!) card is encrypted, but for some strange reasons sometimes Android doesn’t work to well with its own encryption. This means that sometimes your files may become simply broken.

I had this problem with MP3 ringtones. From one day, without any particular reason, my phone started to emit some sound garbage as ringtones instead of my favorite songs. Quick analysis proven that poorly supported encryption plus even more poor MTP protocol plus broken connection between PC and Android resulted in files being broken.

Failures: Quora.