I had slightly different results last night at choir practice. As I mentioned above, when we first tried to do a restore, it came back instantly as though it hadn't done anything. So last night, I first created the same folder structure for Removable Storage Location as I have on my tablet, and I set that folder as the RSL. This time when I did a restore, it displayed an error message that was something like "Corrupt file, skipping data" for about a minute, then it displayed another message saying that the restore was complete but that not all songs were processed (I'm sorry for the inexact messages, but I didn't have time to take a screen shot or write down the exact text). I tried a restore twice, once with the location set to SD Card, and once with it set to Removable Storage Location. I got the same results both times.
However, here is the punchline: after trying these restores, I discovered that her tablet has 3.8 (from the Amazon App Store). I told her that the version mismatch was most likely the reason why the restore failed. Unfortunately, there was no wifi available at practice last night, so we couldn't update the app. She will update the app to 4.0.x and we'll try again next time.
Addendum: It looks like the latest version on the Amazon App Store is 4.0. Do you see an issue with restoring a 4.0.1 backup into 4.0? Or should I wait until she can download and install the 4.0.1 update?
However, here is the punchline: after trying these restores, I discovered that her tablet has 3.8 (from the Amazon App Store). I told her that the version mismatch was most likely the reason why the restore failed. Unfortunately, there was no wifi available at practice last night, so we couldn't update the app. She will update the app to 4.0.x and we'll try again next time.
Addendum: It looks like the latest version on the Amazon App Store is 4.0. Do you see an issue with restoring a 4.0.1 backup into 4.0? Or should I wait until she can download and install the 4.0.1 update?