How do I restart the iTunes matching process? My main iTunes library was in the process of uploading to iTunes Match when I enabled iTunes Match on iTunes on another computer. I got a message saying that only one computer at a time could upload to iTunes Match, and because there were only a handful of items in my library on my secondary computer, I decided to interrupt the upload on the primary computer and quickly do the match on the secondary computer.

Unfortunately, once I did that, the "iTunes Match" sidebar item disappeared from the primary computer, and going into "iTunes Match in the "iTunes Store" just shows a page describing what I can do with iTunes Match.

How do I get my primary computer to resume the upload process?
In the menu bar, select "Store" -> "Update iTunes Match":



The match and upload process will restart.