This worked!!! Thanks very much. Just FYI, in case it helps others.... I have a Intel MacBook Pro (16-inch, 2019). External Monitor: Philips 32" 4k (PHL 328P6VU), plugged in via USB-C. The monitor worked yesterday fine with Big Sur. I updated to Monterey about 16 hours ago and the Philips stopped working. Ie. MacOS > Sys Prefs > Displays > NOTHING detected except the macbook monitor. NOTE: I tried another monitor (LG 4k 42.5" connected via USB-C). It did work, first go. Monterey seemed to like the LG monitor (but not the Philips). To fix the Philips 32" monitor: With Macbook still on and plugged in to Philips, I powered off the Philips 4k, then powered it back on and voila. it was detected virtually immediately.