While not all Android phones offer SD card storage, those that do will sometimes let you make the SD card your default ...

That way, it serves as a back-up storage medium. If anything happens to the data on your phone, you can easily access them on your SD card and restore them back to your phone.

If your PC does not recognize the card, you may have disconnected your card during writing. In this case, you can try to recover your files with tools such as Recuva, Restoration or Undelete Plus. If ...