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My Windows 10 PC has three monitors, and I run X-Plane on the center one as well. I did run into some startup problems with XP failing to remember the monitor of my choice. However, I use only the center monitor for X-Plane, but I hope what I’ve discovered can help. The key I suspect is X-Plane likes to start on Monitor 1. Therefore, I have my three monitors arranged as 2-1-3 in Windows’ Display setting (with 1 being the center and 3 being Windows’ Main). My current setting is quite stable, i.e., XP always starting on the center monitor.
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