I have the same issue. Updated the latest firmware and tried on multiple versions of macOS. I do not have access to a PC to test. One thing I noticed is that my macOS now detects the webcam when it's popped down, but does not detect it when it's popped up. Whenever I pop it down or pop it back up, the Dell display's status indicator shows for a few seconds. It worked fine for the first few months, then one day it just wouldn't detect the webcam unless the pop-up was closed! I tried to get Dell support but it's showing as out of warranty, even though I bought it from Amazon only 4 months ago. I tried registering the product, but could not do it because it requires a PC software.