Minecraft auto launches to second non-existent monitor, and there's no second monitor detected in settings.
Windows 10 detects two monitors when trying to launch Minecraft, even though there's only one
Dustin Nelson 26.06.2017
It's launching off-screen. Try playing with resolution. Make it as big and small as you can. That might cause it to get pushed back on the screen.
Thread Dangler 26.06.2017