Apple says that you shouldn’t use a camera cover with your MacBook webcam, at least not without removing it when closing the laptop, otherwise you run the risk of potentially damaging your screen.
The warning comes in an Apple support document, as spotted by MacRumors, and the issue would seem to be tied in with reports that have come in from some MacBook owners complaining that their screen has suffered from cracks.
The reason damage could occur, Apple notes, is because the construction of its slim MacBooks doesn’t give much breathing room between the screen and the keyboard deck when the notebook is closed.
Apple explains: “If you close your Mac notebook with a camera cover installed, you might damage your display because the clearance between the display and keyboard is designed to very tight tolerances.”
Why would you want to cover your webcam anyway? Some users do so for privacy reasons, not trusting that their camera might be hijacked in some manner (remember the famous cases of Mark Zuckerberg taping over his webcam, and indeed the director of the FBI).
However, Apple further explains that there is a green light to clearly show when your camera is active, if it has been hijacked.
Apple says: “The FaceTime HD camera built into your Mac computer is designed with your privacy in mind and uses a camera indicator light that glows green when the camera is active. So you will always know when the camera is on. The camera is engineered so that it can’t activate without the camera indicator light also turning on.”
Furthermore, Apple observes that covering the camera may prevent some of the laptop’s features from working as well, such as automatic brightness adjustment (via the ambient light sensor) and True Tone technology.
If you must use a webcam cover, Apple advises that it shouldn’t be thicker than a piece of printer paper (0.1mm), or if you do use a thicker cover, make sure that you remove it before closing the MacBook. Otherwise, you may run the risk of cracking the display. You also shouldn’t use anything that leaves an adhesive residue on your camera, for obvious reasons.