i had the problem of offline mode not allowing songs to be played offline; like when commuting to work, etc. I learned here that you need to open the app on the device where you have it installed, make sure all the tabs for each playlist are green for offline, then select File, drop down to offline mode, and a checkmark should appear next to it...then log out of spotify. log back in and play as usual. your songs should now play on your offline device as well. No need to reselect offline mode under File. I have my app loaded on my macbook at home, and use my ipad to listen to when I am away from any internet connection. hope this works!
