After using Finder to make a copy of my project, the iPhone Simulator crashes giving me an NSInternalInconsistencyException error. I subsequently used Time Machine to restore the project before I made the copy, but am still getting the NSInternalInconsistencyException error.
This is a small homework assignment and re-creating it wouldn't be the end of the world. My big concern is that I don't understand something fundamental about how Xcode is working. Any illumination would be greatly appreciated.
Update
Apple identified the bug. The iPhone Simulator keeps the last-run version of the app onboard, and doesn't replace it with the copied/Time-Machine-Restored version that is in Run-and-Build. Deleting the app from the iPhone Simulator and performing a new Run-and-Build resolves the issue.
Sounds like a bug. Your source code files should be fine, so hopefully it's not a big deal to just create a new project and add those files so that you can get back to work. You might also want to report the issue to Apple, especially if you can make it happen again.