Xcode 4 - Error Starting Executable

At a guess, the schemes it set up for you based on your v3 targets and build settings might not be quite right. From the schemes menu, choose to edit the current scheme, then select the Run action from the list and make sure the appropriate exectuable is selected.

I ran into the same issue this question came up so I spent my time identifying the issue, reproducing the issue, narrowing it down and explaining as best I could how to not make it happen - as well as the general frustration that comes with an issue like this (it hit me on 2 different versions of Xcode in 2 weeks).

If you're going to delete my post then at least take the time to try and answer the question as I had tried to do.

Now, on to the reply that actually tells how this issue may be created and how to avoid that.

I JUST had this happen creating an app for iOS. Why? I renamed my target executable.

Just tested this by checking out a new copy of the source and rebuilding.

The app ran fine on my device.

Went in to Xcode 4.2, renamed the target. Ran the app. "Error starting Executable..."

I changed the filename back. Same error.

Cleaned and ran the app again and it launched.

Renamed the app, cleaned and ran it again. Not so much luck.

Don't rename your app by renaming the target.

This is such a stupid limitation. Apple lets you rename your target app, but by doing so, this prevents your app from launching on the device.

EDIT: I haven't checked in any code, but now I can't check out and build and run any app without this happening. How do you get the device/xCode out of this state once you've gotten it in to it?

Even the app now crashes on launch at int retVal = UIApplicationMain(argc, argv, nil, nil);

This is in Xcode 4.2 on Snow Leopard, but I got into the same state with Xcode 3 on another Machine last week.

Edit 2: Rebooted the device, rebooted my Mac. Built and ran in the simulator first, then on the Gen4 iPod touch. It works.

I had this issue when migrating a project from Xcode 4 to 4.1, and it ended up being due to the Target's "Product Name" being different in the debug and release configurations. A holdover from when I changed the name of the product many versions ago. So check that...