Headphones suddenly not recognised

[Paddy Landau]

Out of the blue, my computer has suddenly stopped recognising my headphones.

When I plug in my headphones, the sound still comes out of the computer's built-in speakers; the headphones are silent; and the sound properties settings window (see screen-shot) does not show the headphones.
Sound properties settings window.png

I do not recall making any changes to the computer since they last worked (yesterday), apart from the regular updates.

I have tried restarting the computer, but of course that made no difference.

I have Ubuntu 12.04 64-bit fully updated.

How can I get my headphones to work again? How can I diagnose the problem?

[Paddy Landau]

Well, I rebooted into Windows and had a similar problem (although Windows did recognise that I was plugging in the headphones, apart from a message, it ignored it).

Then the problem went away by itself.

So, I rebooted into Ubuntu, and it's working properly.

Go figure

Marking as solved, although I have no clue how!

[kagashe]

Well, I rebooted into Windows and had a similar problem (although Windows did recognise that I was plugging in the headphones, apart from a message, it ignored it).

Then the problem went away by itself.

So, I rebooted into Ubuntu, and it's working properly.

Go figure

Marking as solved, although I have no clue how!

May not be plugged in properly or cable fault first time.

Kamalakar

[Paddy Landau]

May not be plugged in properly or cable fault first time.

Could be. If it happens again, I'll test on another computer.