Two monitor guest stop working

[Pimol]

I use to run guest on two monitor, my system have 3 screens. By last week I have to work with only two monitor, and I can't adjust the guest screen for the native resolution of them (1366x768 and 1280x1024).
Today I've installed the third one (1920x1080) but i cant use it, or use two of the other monitor with VM: the virtual screen does not attach the physical screen I set, and none of them want work with native resolution.
These o Windows guest (W10 64 bit); with UBUNTU gest I don't had yhis problem...
(I'm using the VM 6.022 r137980 version, a HP i7 with 32 Mbyte RAM)

Any help is appreciated. May be there are a way to force the resolution via console?

[scottgus1]

It has been a really long time since I ran a guest with multiple monitors, and it was not a laptop with normally-removable monitors, so I never had to troubleshoot it.

My first suggestion would be to check the monitor layout in the guest OS. See if yuo can get the guest OS to forget about the extra monitors that Virtualbox provides, go back to 1, even though the 'hardware' is there. Then reboot the guest and try to reset to use the extra monitors.

If this doesn't work, shut down the guest, and take the extra monitors out by setting the monitor count back to 1, then start the guest. Get the gust to use just the one monitor correctly, then shut down again and set back to multiple monitors. Restart the guest and try setting up the monitors again.

Note, if you have done all the above, then regrettably I cannot think of anything else.