App won't launch on device or simulator

Question

So... this is beyond strange.

I had an app that was running perfectly fine in simulator and on device. I've actually already submitted the app and it is for sale in the App Store.

Today I went back in and made a few changes for an update. The app now will not load on my device and it won't load in the simulator.

In the simulator it says "Attaching to app_name" (it lists the actual app name) and it stays on this process of "Attaching" indefinitely, while the Simulator screen is entirely black.

When running the app on the device it says "Build Succeeded", then "Finished running app_name" without anything ever showing up on the device.

I restarted XCode and tried restarting my computer, but still no luck... Other apps do work, but not this one.

Any ideas?

EDIT: I just started a brand new project, copied over all the assets and code, tried running and STILL the same thing happened. I thought for sure creating the project anew would work...

FINAL EDIT: After running "Clean", deleting the DerivedData folder, and restarting my computer a SECOND time, the new project (with all assets copied over) is now working. The original project still does not work. So I am not sure what caused the issue and what fixed the issue, but for me at least I can now move on. What do I do with this thread? Can it just be deleted? Thanks everyone who chimed in to try and help!

Answer 1

Tried above options but didn't work for me.

Finally, Just Resetting Simulator did the trick.

Answer 2

In the options move the DerivedData into your project directory. Whenever I have problems with xcode4 I just quit it and delete this directory. It contains the builds and caches of the background compiles that xcode4 does.

Deleting this folder usually fixes all problems I get.