How to stop mac from moving windows from external display to laptop when opening laptop lid I have an external monitor connected to my MBP via HDMI. I can use my laptop in 'clamshell' mode, where I close the laptop's lid and work off of my external monitor.
The problem I have is that when I open the laptop's lid some of my windows move off the external monitor to the laptop. Some trial and error shows that if a window is on the laptop when I close the lid, that window will reappear on the laptop if I reopen the lid, even if I move the window around while it is on the external monitor.
How can I prevent my mac from moving windows to the laptop. I want all windows to stay on the external monitor until I physically move them to the laptop, and once I close the lid they should stay on the external monitor even if I re-open the lid.
Welcome to Ask Different. I think your experimentation has you on the right track. If you drag a window to the external monitor before closing the lid on your laptop, it should stay on the external monitor after opening the lid again. You may also want to check which monitor you have as primary - that's where your desktop icons will first appear. In System Preferences, go to Displays and then click on the Arrangement tab. The display with the white bar on top is primary. You can drag that bar to the other display to make it primary.