No sound from laptop speakers in Ubuntu 14.04 after booting into Windows 8.1

Windows 8 includes a new feature called "Hybrid Shutdown" or "Fast Boot". This process is described in the article "How Windows 8 Hybrid Shutdown / Fast Boot feature works". Basically, on shutdown Windows kills all the user processes, and then hibernates the kernel to disk. It does this to speed up the shutdown and boot up process. Killing all of the user processes is faster than hibernating them to disk, and restoring a hibernated kernel is faster than a fresh boot of the kernel.

Linux users are advised to turn off "Hybrid Shutdown / Fast Boot", otherwise they will be unable to mount NTFS filesystems (because the current state of the NTFS filesystem is not stored on the NTFS partition, but held in the hibernated kernel memory). From this question it also seems that it can interfere with device initialisation - probably by putting the device into a sleep state from which it does not awake when a normal boot process is carried out.

I had a similar problem with my laptop (Samsung Series 7 Chronos) on Ubuntu 14.04 LTS (dual booting with Windows). Since the introduction of Windows 8 (and following the upgrade to Windows 10) the speakers would constantly stay on mute (even though the volume settings would suggest otherwise).

After some research online I discovered the Sound Troubleshooting Procedure. The step 1A of the procedure fixed the problem:

killall pulseaudio; rm -r ~/.config/pulse/* ; rm -r ~/.pulse*

(i.e. it ends/kills all processes running pulseaudio, and it forces PulseAudio to reset its user configuration by deleting files and folders that were created in the user home folder)

wait at least 10 seconds then run the following command:

pulseaudio -k 

(i.e. it kills pulseaudio daemon)

For additional information concerning the aforementioned commands you might wanna check these links: Ubuntu Manuals - killall, Ubuntu Manuals - pulseaudio, Ubuntu Wiki - PulseAudio.

If these simple commands did not solve your problem, I suggest you to go through the alternative steps provided by the sound troubleshooting procedure.

As a final note, a trivial solution that worked for me: while in Ubuntu, plugging in and out the headphones would re-enable the audio from the speakers.

What is the cause? It appears that the PulseaAudio configuration is corrupted/unsynchronised and does not reflect the current status of the sound system. Yet, I don't know the exact event causing the inconsistency.

This is a pretty straight forward problem. I believe that Linux places your headphone jack in a state that Windows can not recognize.

I have found that doing a cold shutdown (Holding power button for 10 sec.) of Linux and then booting into Windows will often fix this problem.