Q: isight not working after 10.9 update

You could try a PRAM reset: http://support.apple.com/kb/ht1379

That's a pity. If you havent already, try a Safe Boot, which runs some maintenance processes and may help:

Restart holding down the Shift key until you see the grey progress bar. Input your admin password when prompted and once booted test the webcam (TBH I'm not certain if even under normal circumstances the webcam will actually work in Safe Boot as the Mac is in a kind of limited mode - no harm testing though).

Restart from the Apple menu to return to normal boot.

Have a look at the 'More LIke This' on the right >>>>>>>>>>>

EZJim has posted a couple of links and suggests a possible re-install of the OS.

Bridgers872 wrote:... Updated to 10.9 now the isight doesn't work... I tried to reinstall 10.9 I get the message that 10.9 can not be installed on this machine...

Because you have already updated to 10.9, you KNOW that 10.9 can be installed on your MBA.

Shut down (do not merely use the  > Restart...) menu command.  Wait about one minute before you start your MBA again.  Then follow Apple's instructions to Reinstall OS X Mavericks.

Now try your camera again using the method suggested in How to Troubleshoot iSight.  (Over time, Apple has changed the built-in camera's name on newer Macs from "iSight" to "FaceTime" and then to "FaceTime HD."  Regardless of the name of your Mac's built-in camera, the same troubleshooting method and remedies apply.)

Message was edited by: EZ Jim

Mac OSX 10.9

My camera also seemed to not be working after 10.9 install on my iMac. I tried a shutdown/restart and still no camera. BUT, I went to the Video menu in Facetime and noticed that my other "camera" which is a video capture device, was checked. I simply checked built-in iSight instead and voila! it's now working.

For me, it will work after a restart. But then will randomly stop working again. This has happened twice.