I used MMR and android 7. Left android to DL for 30 min and got an empty file; just headers.
Sometimes sensors go in bad state and they can't stream or log anything. In this case use mbientLab android app to reset your sensor (also reset your bluetooth on your phone). I know that bluetooth on Android is #$@ but i think mbientlab have to find a better way for fixing these kind of problems.
I'm having the same issue. Seems like we don't know what exactly the issue is so we have to run through a host troubleshooting... Is that right? How do we know when we start a session, that the 'sensor is not in a bad state'?
Take a look at our troubleshooting page and our "erase" script which I posted to you in the other thread: https://mbientlab.com/tutorials/CppDevelopment.html#reset