VirtualBox turns off additional displays after loading the Guest Additions.

[maul]

I have a Windows 10 virtual machine with 9 virtual displays in 1920 * 1080 resolution. After rebooting, before logging in, I can see all 9 displays, but after logging in and loading the Guest Additions, 7 displays go to the off state, the resolution of the main one changes to 1920x975. How can I prevent the displays from turning off? The main purpose of this virtual machine is to display information on 9 monitors.