Could not launch "<appName>" failed to get the task for process <processNumber>?

Using Xcode 4.5.2 and building for iOS4 or newer, I get this message when building for my device (iOS 6.0.1 on 4s). I dismiss the dialog then relaunch the app on my device which seems to work. I am newer to iOS development, so I aplogize in advance if this is a silly question.

Thank you in advance for your help.

My issue was using Distribution provisioning profile for signing the app, once I made a development provisioning profile, the app installed and ran on iPhone just fine.

The answer seems to be "you need to fix your provisioning profile", but can happen for several reasons, as indicated by other answers on here.

In my case, I hadn't added a new device to an existing developer provisioning profile, so I just re-created the profile with the new device, and it worked!

In my case happens all time I add a new device ID then update the provision profile, download and "install it on Xcode 5".

To fix this:

• Go to Xcode>Preferences>Account Tab>Select Apple ID>View Details>Refresh Button (Bottom left corner).
• Reinitiate Xcode.

Start again the app, you will be able to test the app in the device.

Here's what my situation was and how I solved the problem:

• I had been running the app from Xcode to my phone and all was fine
• I switched to a different code signing identity (I had to change the bundle name also to match)
• I ran the app to my phone and got the error. The app would install, but not open.
• Did a bunch of stuff like Clean, close n open Xcode; delete the app from the phone. All to no good effect.

SOLUTION: turned the phone off n on.

Coincidence?  I think not.   :-)