@JMCIVOR I tried removing & reinserting the card, it didn't work. The only thing that did work was to re-format the card. It works now, but means I lost the videos I actually cared about downloading.

Trying to download playback from the SD card and the app won't do it. Just says "network is unstable. Please try again later" When I look at the video in downloads, it gives the loading bar for a few...