Error code

Android INSTALL_FAILED_MEDIA_UNAVAILABLE

ANDROIDINSTALL_FAILED_MEDIA_UNAVAILABLE
Android Error Code· An error code shown by Android or the Google Play Store.

What it means

The APK cannot be installed to external storage because the storage is not available.

How to fix it

  1. Reinsert and mount the SD card.
  2. Install the app to internal storage.
  3. Restart the device to remount the SD card.

Not affiliated with Android. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.