My wife was ignoring nagging messages to update macOS Sierra on her 2011 MacBook Air so I did it for her, all good.

The problems may range from difficulties connecting to wi-fi networks, dropping wi-fi connections (particularly after waking from sleep), sluggish wireless speeds, and other frustrating connectivity problems. Some MacOS High Sierra users have reported issues with wireless networking after updating their Mac to the latest system software version.

Some older cameras made for Windows PC's may not work on Apple Macintosh computers, or Mac web camera drivers may not exist. They're simply Plug and Play on modern Macs running MacOS Sur, Catalina, Mojave and Sierra, as well as OSX El Capitan, Yosemite, Mavericks, Lion, and Leopard. Mac Webcams That Just WorkLooking to buy a driver-free, fully Macintosh compatible webcam? Have USB 2.0, 3.0 or 3.1 ports? The external webcam models listed here are UVC - USB Video Class compliant. So it doesn't necessarily mean that the macOS installation is frozen when the Mac stay at “20 minutes remaining” for two hours. Sometimes, it just takes a very long time for you MacBook or iMac to install the macOS Sierra or High Sierra update. 1.Check If the Install is Still Going on. Troubleshooting macOS High Sierra Install Problems. That means any UVC compliant external USB camera should just work when plugged into a Mac's USB 2.0 speed or faster port. Apple's UVC Kernel Extensions are built into MacOS Big Sur, Catalina, Mojave and Sierra, as well as OSX ElCapitan, Yosemitie, Mavericks, Lion and Leopard.

High sierra macbook air troubleshooting