I've just bought a 64GB micro SD so I can carry a bunch of music and photos around on my phone running Lollipop. For security reasons it is intentionally not rooted. When I try 'Save to SD card' having selected a track on my WDMyCloud, or having selected a track in my Downloads, I then select a folder, and it appears in the Activity log, but after a while it just fails:
I found that file managers have a similar issue, but they provide a mechanism that allows me to give permission permanently, though I have to say it was very, very obscure (Select All button while viewing the root folder - don't get me started!).
Doing some research, I wonder if this could be something to do with changes introduced in Android 4.4 - see http://m.androidcentral.com/lollipop-brings-changes-way-your-sd-card-works-kind-youll
Any suggestions how I can get to use the nice keep-in-sync features the My Cloud app offers re. files downloaded from my NAS, but to the SD card? At the moment I am limited to the few free GB in my phone memory, and have to use a 3rd party file manager to get them onto the SD card.
P.S. A possibility related problem is that Delete in the My Cloud app Downloads folder does not remove the files from storage - it just removes them from the app, taking up space on the phone until I delete them with a file manager. Is this also a permissions thing? Maybe I should just go Apple, 'cause "it just works", or so they say.