Google Music is one of the coolest ideas from the search giants that allow a user to upload music to the Google Music server and stream it via any mobile browser, which means you always keep your favorite music with you anywhere you go but that requires a 3G or WI-Fi obviously. Having said that, Google Music isn’t a perfect service either and has indeed some flaws. Google has always been pretty good in addressing and fixing the issues that their users have been asking them to fix but there has been one thing that Google hasn’t fixed yet and that was downloading the music off of Google Music.
Though still the Google hasn’t fixed it yet but now there’s a way to download the music off of Google Music onto your SD card and this method is compatible with any device that can run Google Music.
The drill is pretty simple. When you listen to a song, it buffers and when it’s done with the buffering thing navigate to the place where Google Music saves all the completely buffered songs. Now just simply copy the MP3 file on your SD card, rename it and you have it. This is extremely handy when there isn’t any internet connection available around you but if you are trying to download the whole of your stuff from the Google Music then this wouldn’t be a good idea. In case you want to download all of your stuff off of Google Music then you should have Music Manager for your desktop that is specially designed by Google to deal with that sort of thing.
Source: XDA Developers