Question : Problem: Cannot adjust sound on macbook pro laptop

I can't adjust the volume on my computer. It's as if it's muted (no sound comes out) but I can't adjust the volume control. As you can tell from the attached screenshot, the selection arrow is not filled in. Unlike the other controls, it will not allow me to adjust it. Please advise. Thanks for your help!

Answer : Problem: Cannot adjust sound on macbook pro laptop

I'd like to see a screenshot of the "Output" tab.  What displays on screen when you try to press the volume change keys on the keyboard?

I ask because I have this problem all the time, my laptop "forgets" that it has built in speakers.  Normally a restart solves this, though you may need to re-install your system.