I noticed this problem yesterday when trying to download Mavericks. I don't use the Mac App Store too often, but this was the first time it never worked for me. I clicked on the Free Upgrade button next to Mavericks, then clicked Install, then it said Downloading. I went to the Purchased tab, and it shows up, but with a gray Download button. I click it, it fades out, the little spinning symbol shows up next to the 'forward/back' buttons, and then it immediately goes back to gray and still says Download. I tried downloading another free app to no avail. I searched around and did these things to try and troubleshoot, with none of them working. 1. Restarted. 2. Downloaded updates within Software Update. 3. Deleted the storeagent in the Activity Monitor. 4. Entered these commands in the Terminal: rm -r ~/Library/Caches/com.apple.appstore rm -r ~/Library/Caches/com.apple.storeagent rm ~/Library/Preferences/com.apple.appstore.plist rm ~/Library/Preferences/com.apple.storeagent.plist rm ~/Library/Cookies/com.apple.appstore.plist 5. Went into iTunes and downloaded the free single of the week to make sure it wouldn't ask me to agree to new terms of service, etc. 6. Verified my credit card info in my account. Does anyone have any other ideas to try? Kind of stumped here.