Hi again all- I've now gotten two Kingston 64 Gb OTG MicroDuo 3.0 for Android flashdrives (from walmart.com, 5 yr warranty & under $20 each including tax & free pickup- sku #: 554355664). I know they work OK, because I've copied stuff from my laptop to'em and played back on my Droid. Where I'm having trouble is getting familiar with a routine for backing up files, which I need to do reliably, as my timelapse & video shots are on the large side. The generic File Manager recognized the external drive, but I couldn't make it do any file transfers. I found reference online to using the Astro File Manager (but the rest of the instructions are obsolete and don't track on my Droid Turbo). I get that the basic idea is to Copy and then Paste from Internal onto the External drive (instead of drag&drop), which I've managed to do successfully a couple times, but I keep getting this intermittent nag about permissions. Also, I'd like to know how to unmount the USB drive safely without shutting off the Droid completely... Anybody got a good standard procedure? Is there an external drive app that does backups, timed playbacks, etc?