I had been tracing an app deployed via xcode - so that wasn't the problem. "You are currently not able to see traffic of other processes doing networking work on behalf of your app (e.g. WebKit views or video streaming handled by AVFoundation)." That must be the problem I'm having. Hooked into a portion of our app which was doing URLSession request directly and did see the traffic. Thanks for the help. Looking forward to the day when AVFoundation traffic will be observable. This is a big limitation for using instruments to diagnose video streaming apps.