How to Reset Mac SMC and NVRAM to Fix Webcam Detection Failure

SMC (System Management Controller) governs low-level hardware behavior — power, thermal management, and on some Mac models, peripheral initialization including the camera. NVRAM (previously called PRAM) stores a small set of settings that need to be available very early in the boot process, before macOS itself has fully loaded.

Both are appropriate to try specifically when a camera is not detected AT ALL by the system — missing from System Information's Camera page entirely, not just failing inside one particular app — and only after you've already confirmed the camera isn't disabled in Device Manager-equivalent settings or blocked by a straightforward permission issue. Resetting either one is safe and reversible, but it also resets several unrelated settings (like display resolution defaults or startup disk selection) back to their factory defaults, so it's worth trying more targeted fixes first.

Step 1: Shut down your Mac completely.

Don't just close the lid — use Apple menu → Shut Down.

Step 2: Press and hold Left Shift + Control + Option, plus the Power button, all at the same time, for about 10 seconds.

Step 3: Release all keys, then press the Power button normally to turn the Mac back on.

This general procedure covers most modern Intel MacBooks with a built-in, non-removable battery. A small number of older or unusual configurations use a slightly different combination — Apple's own support documentation for your exact model is worth a quick check if this doesn't seem to register.

Step 1: Shut down your Mac completely.

Step 2: Power it back on, and immediately press and hold Option + Command + P + R

Before the grey startup screen appears.

Step 3: Keep holding for about 20 seconds.

On Macs with a startup chime you'll hear it twice; on newer T2-equipped Macs, the Apple logo will appear and disappear twice instead.

Step 4: Release the keys and let the Mac finish starting normally.

↑ Test your camera with the widget above once it's back up.

Apple Silicon Macs (the M1 chip and later) do not have a user-accessible SMC reset or the traditional NVRAM key-combination reset — this is a genuine architectural difference, not a missing feature. Apple's official guidance for equivalent issues on these Macs is simply a full shutdown and restart, since much of what SMC/NVRAM used to manage is now handled automatically as part of the chip's own power-management system.

If a full shutdown and restart doesn't resolve a camera detection failure on an Apple Silicon Mac, the next genuine steps are running Apple Diagnostics (hold the power button during startup until you see the options screen, then look for a diagnostics option) or booking an appointment with Apple Support, since this points toward something that generally needs first-party hardware-level diagnosis on these newer Macs.

What are VDCAssistant and AppleCameraAssistant, and why do they matter for camera problems?

These are macOS’s own background processes for managing camera access — VDCAssistant coordinates the camera hardware itself, and AppleCameraAssistant works alongside it. If either one gets stuck, commonly after an app crashes without properly releasing the camera, every app can show the camera as unavailable until both are reset. Opening Terminal and running sudo killall VDCAssistant AppleCameraAssistant forces a clean restart of both, which resolves a large share of stuck-camera and black-screen issues that a simple app restart doesn’t fix.

What is UVCAssistant, and is it different from VDCAssistant?

On some macOS versions, Apple introduced UVCAssistant as an additional process specifically for USB Video Class (UVC) compliant external webcams — the standard most third-party USB cameras follow. If you’re using an external webcam rather than the built-in camera, and killing VDCAssistant alone doesn’t resolve a stuck camera, check Activity Monitor (View → All Processes) for UVCAssistant specifically and force-quit it the same way.

Does Apple Silicon (M1/M2/M3/M4) handle the camera differently than Intel Macs did?

Yes — Apple Silicon Macs route camera video through the chip’s own dedicated image signal processor rather than the path Intel Macs used, and the exact background processes involved can differ across specific Apple Silicon generations. If a fix written for an Intel Mac, or for a different chip generation, doesn’t fully apply on your machine, checking Activity Monitor’s actual running process list — rather than assuming a name from an older guide — is the most reliable way to identify what’s genuinely holding your camera.