Background
In Android 4.4 (KitKat), Google suddenly cut off all third-party (non-preinstalled) applications from the permission to write to external/removable storage. Thanks to this decision, a lot of applications have been crippled and some have become entirely useless. Pressure on Google has led to a compromise solution that has been integrated into Android 5. Applications can regain the write permission to external storage using a new API together with SAF (Storage Access Framework). However, in general, external SD cards are always much less reliable (especially some combinations of devices/SD cards) than an internal memory.

First Start

Limitations
There are some limitations in the SAF mode you should know.