You might see green pixelation or video distortion when you play video content that you bought from the iTunes Store on your Mac if you:
- Installed macOS High Sierra on one volume and started up from another volume that uses an earlier version of macOS; or
- Installed macOS High Sierra on your computer, then reinstalled OS X Yosemite or earlier.
To resolve the issue, continue below.
Resolve the issue
If you're using macOS High Sierra, Sierra, or OS X El Capitan, install all available updates for that operating system.
If you're using OS X Yosemite or earlier, learn how to upgrade to macOS High Sierra through the App Store on your Mac.