Xcode can’t launch project for debugging

Question

I’m using Xcode 4.6.3 to build a library for OS X. My project includes a target called LibraryTest, which is a command-line app to test the functionality of the library. Both the library and the test app build fine, but when I try to run the app it quits immediately and the debug console shows:

error: failed to launch '/Users/bdesham/Library/Developer/Xcode/DerivedData/Wavelength_and_Spectrum_Library-byosniusyaoidgdcpzwzuzkitzgv/Build/Products/Debug/LibraryTest'
-- error: Host::LaunchProcess (launch_info) => pid=0,
path='/Applications/Xcode.app/Contents/SharedFrameworks/LLDB.framework/Versions/A/Resources/debugserver'
err = error: ::posix_spawnp (
    pid => 98649,
    path = '/Applications/Xcode.app/Contents/SharedFrameworks/LLDB.framework/Versions/A/Resources/debugserver',
    file_actions = 0x10b09e268,
    attr = 0x10b09e2a0,
    argv = 0x7fe2701377e0,
    envp = 0x0 )
err = Bad file descriptor (0x00000009) (0x00000009)
error: failed to launch '/Users/bdesham/Library/Developer/Xcode/DerivedData/Wavelength_and_Spectrum_Library-byosniusyaoidgdcpzwzuzkitzgv/Build/Products/Debug/LibraryTest'
-- error: Host::LaunchProcess (launch_info) => pid=0,
path='/Applications/Xcode.app/Contents/SharedFrameworks/LLDB.framework/Versions/A/Resources/debugserver'
err = error: ::posix_spawnp (
    pid => 98649,
    path = '/Applications/Xcode.app/Contents/SharedFrameworks/LLDB.framework/Versions/A/Resources/debugserver',
    file_actions = 0x10b09e268,
    attr = 0x10b09e2a0,
    argv = 0x7fe2701377e0,
    envp = 0x0 )
err = Bad file descriptor (0x00000009) (0x00000009)

(Line breaks added for readability.) I have the Xcode 5 DP installed, so I tried removing Xcode 4 and reinstalling it from the Mac App Store, but no dice. Deleting DerivedData didn’t help either. Any ideas?

Answer 1

Restarting my Mac seems to have fixed this.