Background
In Android 4.4 (KitKat), Google restricted third-party (non-preinstalled) applications from writing to external/removable storage. This decision crippled many applications, making some useless. Pressure on Google led to a compromise solution integrated into Android 5. Applications can regain write permission to external storage using a new API with the SAF (Storage Access Framework). However, generally, external SD cards are always much less reliable (especially certain device/SD card combinations) than internal memory.

First Start

Limitations
There are some limitations in SAF mode you should be aware of: