I've been working on an Ionic Framework project for a while now. Just recently after I upgraded to Xcode 7, however, I couldn't get a project to install on the iOS simulator. Every time I would build an emulate the project, the process would fail with an "Invalid device state" error. I tried a number of things: rebooting my machine, reinstalling Xcode, etc. What I discovered, however, was the root of this problem had nothing to do with Xcode 7, but instead with file permissions.