xcode4 - Error: No executable file specified -

suddenly program runs , compiles without error not open executable. error dialog:

error starting executable... no executable file specified. use file or exec-file command

i think may have started when created "workspace" of same name. did searches error found nothing made sense.

i hate have copy work on new project because of this. help!

could bug?

if using gdb default debugger (verify under product-edit scheme menu) must specify executable path contained under app folder (executable.app/contents/macos/executable).