If your iSight does not work in any app, the SMC reset suggested
in Apple's iSight Troubleshooting suggestions may restore proper function.
Otherwise, use Disk Utility to repair permissions and then
download and apply the 10.7.2 Combo Update:
Repair permissions again immediately following the system restart
that completes the Combo update. The Combo version of updates
can sometimes correct problems that appear after an OS X update.
If your only problem continues to be in Skype, be sure you are
using the latest Skype: http://www.skype.com/go/downloading
Message was edited by: EZ Jim
I know this is an older thread BUT I've been dealing with this issue for the past four days and this is what I found... (perhaps if it helps another person....)
Assuming you've already checked while on a Skype video call that your camera isn't turned off...
Open Skype Preferences to verify your settings.
(prob in your downloads, applications folder or on your desktop)
Then at the top your screen, next to the Apple Icon you should see Skype:
Select Skype, then scroll down to Preferences. Verify settings.
(Mine, for example, under the "Calls" Tab was set to autoanswer so I can check on
my dogs while away and tell them to get off the couch!)
Make sure another apple app isn't hijacking your camera.
Open Finder, Devices, Applications, then look for IChat
Once open, Select iChat and scroll down to preferences.
(For my settings, I don't use IChat SO I changed the "default IM application" to Skype,
under General settings tab.)
Select the green Audio/Video Tab
and uncheck "Open IChat when external camera is on"
I verified that all other Apps using the camera weren't open. My insight camera worked
when I opened Photobooth, IChat, Facetime and ICamSource (a monitoring program)
- just didn't work with Skype!
From Desktop, go to Apple Icon, select "Force Quit Finder", then scroll down and
close everything that uses the camera.
From Desktop, go to Apple Icon and select Restart (pic same as above).
Upon restarting, once the screen blanks out hold down the following keys all at once:
Option, Command and P and R keys.
For me, I heard the computer "restart song" chime twice before letting go.
(PRAM and NVRAM settings)
I tried a Skype video call from an Iphone to Mac Desktop and it went through just fine!