From what I was able to tell, this exact behaviour when trying to build and run an app on a device:
App compiles without error
App launches on device
App processes and displays first screen
App suddenly quits with no warning or error
Xcode reports that "Process can not be found"
No error logs in the device console or in Xcode are reported
is caused be a distribution profile being assigned to:
Target
iOS Application
Build Settings
Code Signing
Code Signing Identity
Debug
So, if a distribution profile is assigned to an iOS app's Debug build configuration, the app will build properly, launch and quit without a warning, or anything explaining why this happened.
If this is true, then this is really nasty since information on this is scarce and Xcode lets you assign any provisioning file to this configuration.
The only way I was able to track this down was through a 1.5 year old comment on StackExchange about this being a known open bug.
If this is indeed the case, why is something like this still open, why doesn't Xcode report an error when attempting to run with a dist profile and why does Xcode let you apply a dist profile to the debug build configuration in the first place?
For an issue of this consequence to throw no error at all and even be allowed in the first place is pretty bad.
Here's the SE link that refers to the issue