MacBook Pro M1 with an external monitor. For years, the external as Main and the built-in monitor was Extended. After 14.5 update, when a specific user logs on, the built-in monitor "disappears" from Displays and the two monitors show the same desktop. That is as if the external monitor is the only one. If the monitor cable is unplugged, the MacBook boots normally. Plugging in the external monitor following normal boot results in the external becoming Main and built-in Extended. I suspect some launch item install with an app is affecting the display config. I first removed zoom, but no change. There are about 110 apps installed on this machine. How to determine which module or app is doing this? That is, is there a tool or log setting that would note a change in the display settings? I would like to narrow the likely candidates.