iTunes music is missing after updating mac.
So i just updated my MacBook to the most recent update available (the update where it changes iphoto to photos).
Most of my music is missing. I have the music i have purchased off iTunes, but all my other downloaded music is missing. About 800 songs to be exact. I don't know how to get them back and I am very frustrated. Please help!!!
MacBook Air, OS X Mavericks (10.9)