Google Play Music Match

How to tell if a song from Google Play Music was uploaded from your computer or it was simply matched with a copy from Google's servers? Click the 3-dot icon next to the song's name in the desktop interface and see if you can find a menu item called "fix incorrect match". If so, you'll listen to Google's version of the song.

"In order to upload your music quickly, Google Play matches your music files with copies on our server. Occassionally we might match with the wrong song. Report the problem here and the song will be corrected to use your copy instead of the matched copy," mentions Google's dialog.

If you click "fix match", you'll get this message: "Please make sure that the computer where you keep this song is running Music Manager and is connected to the internet. The song will be uploaded again within the next day."

Google's copies have a bit rate of 320kbps, so many of your songs will be "upgraded". You can check this by clicking "edit info".