Dell XPS 14 9440 camera or microphone is not working in calls

The checks in more detail

Make sure that Camera access and Microphone access are on, that the apps you use are allowed, and that desktop apps have access as well; a setting that blocks desktop apps is the commonest reason a video call shows a black picture. Look at the keyboard: the XPS has a touch function row and a key that mutes the microphone and one that switches the camera off, shown by an indicator; press it to see if it toggles. Look for a camera indicator light, and check that nothing, such as a sticker, covers the lens. In the call app, open the settings and choose the correct camera and microphone from the lists, since a connected headset or a virtual camera may have taken over.

In Windows Sound settings, pick the input device and speak, watching the input level move. Quit any app that has the camera, restart, and install camera, audio and chipset drivers through Dell SupportAssist, Dell Command Update and Windows Update. If the microphone is quiet, open the device properties and raise the level, and turn off enhancements to test. In Device Manager, under Cameras and Audio inputs, check for a warning symbol, and if there is one, uninstall the device and restart so Windows reinstalls it. If neither device appears after updates, contact Dell with the service tag.

The XPS 14's thin frame has a combined camera and sensor module, and Dell's software can change how it behaves. Windows Studio Effects, available on laptops with a neural processing unit, adds background blur, eye contact and automatic framing, and a call app that shows a distorted or delayed picture may be fighting with these effects, so try turning them off in Settings, Bluetooth and devices, Cameras. The infrared camera used for Windows Hello is separate from the color camera, and a Hello problem does not mean the camera for calls is broken. Check the privacy keys on the touch function row, and press the camera key twice if the indicator seems stuck.