- Shut down the computer (even if it looks off, hold the power button down for 30 seconds to make sure).
- Plug in the MagSafe power adapter (charger) to a power source, connecting it to the Mac if it's not already connected.
- On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
- Release all the keys and the power button at the same time.
- Press the power button to turn on the computer.
If it starts up but doesn't start properly do this:
- Shut down the computer.
- Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step
- Turn on the computer.
- Press and hold the Command-Option-P-R keys. You must press this key combination before the grey screen appears.
- Hold the keys down until the computer restarts and you hear the startup sound for the second time.
- Release the keys.
Then check in System Report whether it lists the webcam.
Use the System Information app to see a summary of information about your Mac hardware, software and network.
The System Information app provides detailed specifications and other information about your Mac hardware and software, including your network and external devices. In some versions of OS X, this app is called System Profiler.
Choose Apple menu > About This Mac. This opens an overview of your Mac, including your Mac model, processor, memory, serial number and version of macOS. To see the greater detail provided by the System Information app, click the System Report button.
To open System Information directly, press and hold the Option key and choose Apple menu > System Information. You can also use Spotlight to find System Information, or open it from the Utilities folder of your Applications folder.
System Information opens to a system report for your Mac:
The webcam should be listed under Camera as the FaceTime camera.
If it isn't you may have a hardware fault and it will need to be brought in for repair.