No in game sound, requires launcher restart.

I've been having the same problems, too. Whenever I try to launch the game, it starts without any sound in Silent Mode, unless I fidget with the launcher by re-opening it and launching the game until I get sound. I've checked the developer log, and the problem is with OpenAL.

Please attach the output of the development console of the Launcher

This has happened to me since 1.4. Whenever the sound does not load a stack trace is generated saying that LWJGL could not locate the OpenAL library, and then there is sometimes a line saying that the game is switching to silent mode. Since 1.6 there is also sometimes a long (about 30 seconds) delay that ends when some kind of timer triggers and says that OpenAL took to long to load and loading was terminated.

Please attach the output of the development console.

Client> 
Client> Starting up SoundSystem...
Client> Initializing LWJGL OpenAL
Client>     (The LWJGL binding of OpenAL.  For more information, see http://www.lwjgl.org)
Client> AL lib: (EE) MMDevApiOpenPlayback: Device init failed: 0x80004005
Client> AL lib: (EE) MMDevApiOpenPlayback: Device init failed: 0x80004005
Client> Error in class 'LibraryLWJGLOpenAL'
Client>     Unable to initialize OpenAL.  Probable cause: OpenAL not supported.
Client>     ERROR MESSAGE:
Client>         Could not locate OpenAL library.
Client>     STACK TRACE:
Client>         org.lwjgl.openal.AL.create(AL.java:151)
Client>         org.lwjgl.openal.AL.create(AL.java:102)
Client>         org.lwjgl.openal.AL.create(AL.java:201)
Client>         paulscode.sound.libraries.LibraryLWJGLOpenAL.init(LibraryLWJGLOpenAL.java:164)
Client>         paulscode.sound.SoundSystem.CommandNewLibrary(SoundSystem.java:1576)
Client>         paulscode.sound.SoundSystem.CommandQueue(SoundSystem.java:2572)
Client>         paulscode.sound.CommandThread.run(CommandThread.java:121)
Client>     ERROR MESSAGE:
Client>         Could not locate OpenAL library.
Client> 
Client> Starting up SoundSystem...
Client> Switching to No Sound
Client>     (Silent Mode)

Duplicate of MC-20069