Audio output changed to 'Digital Out' and speakers don't work! Please help!

This is WHERE TO POKE (what worked for me that solved this exact problem):

Looking at the port with the red light, first there are 3 tabs [top, left and right] at the same depth into the port. The tab you need to pull down is about 2mm deeper than these initial tabs on the right side (towards the front of the computer).
So, again, what worked for me was pulling downwards on the 2nd (deeper) metal tab on the right side. I used a safety pin with the end bent 90 deg. I also found a bright external light source to help a lot.

Good luck.

Had the same problem. Digital output greyed out and no sound from internal speakers, but when I plugged in headphones, they worked and had the red light.

Solution for me:
Plug in headphones and usb at the same time. I used the iPod shuffle USB cable http://support.apple.com/kb/HT3480 by plugging in the USB side first and then the audio jack second. When I unplugged the audio jack (leaving in the USB), the digital output box, gave me the option for internal speakers.

I'm not so sure that you can deactivate that action.

Sometimes it just sticks every now and then and can be rectified just the way that you did. Perhaps you could take it in to see an Apple Genius and find out what they have to say.

Talked to Tech Support about this when my machine locked up in this same fashion. There's a little "door" inside the headphone jack that can get stuck in the open position and keep the audio from switching back to the internal speakers / stuck in the digital (optical) output position...

The solution: the iPick... It's a toothpick, but if you use it to poke around inside the headphone jack until the little door gets unstuck, it becomes an iPick, and a box of them are very expensive, but they come in lovely colors and are very intuitive to use...

I'm not kidding... Stick a toothpick (or other non-conductive small stick) in the headphone jack and joog it around until it releases the little door...

Not trying to spook you but I had this exact problem a few weeks ago. All of a sudden it had the red light showing so I took it in to an Apple store. They replaced the logic board under warranty and it only took a few days.

I found posts dating all the way back to 2006 on Google about this issue. Now I'm having a problem. Nice to see that in 4 years Apple still hasn't taken care of this issue...

I'm poking around with a hair clip, can't find any switch or release. Tried unplugging/plugging my digital out cable in and out, as well as a headphones cable. Still stuck in digital mode.

Anyone have another trick or a picture of exactly where this switch is on a 2009 13" MacBook Pro.

When you pull out the headphones and look into the audio output jack can you see the little red led glowing?

read all the discussions.....where do I poke to undo little door? been poking and poking without succes.

Cool advice my Macbook Pro worked great with this solution - thx a million