How to have both displays automatically start with guest?

[vb_user_6128]

I have a Windows 10 Host, a Ubuntu Guest, and 2 identical 27" monitors. Until very recently, starting my Guest OS would automatically start both display windows. Now only 1 display window is launched when the guest OS is started, and I have to wait until I am fully logged into Ubuntu before I can launch the second display window.

If I right click "Display" -> "Virtual Screen 2" at any point before being fully logged into Ubuntu, the "Enable" option is greyed out. The "Enable" option does not become available until I am logged into Ubuntu and the desktop has appeared. How can I fix this?

[scottgus1]

Start the guest from full power off, not save-state. Run until you see the problem happen, then shut down the guest from within the guest OS if possible. If not possible, close the Virtualbox window for the guest with the Power Off option set.

Please right-click the guest in the main Virtualbox window's guest list, choose Show Log. Save the far left tab's log, zip the log file, and post the zip file, using the forum's Upload Attachment tab.

[vb_user_6128]

The zipped log is attached.

[scottgus1]

A new Nvidia driver version for your host video was put out with a file that has a portion of its security signature incompatible with Virtualbox's hardening:

00:00:03.356252 supR3HardenedErrorV: supR3HardenedScreenImage/LdrLoadDll: rc=VERR_CR_X509_CPV_NOT_VALID_AT_TIME fImage=1 fProtect=0x0 fAccess=0x0 \Device\HarddiskVolume5\Windows\System32\DriverStore\FileRepository\nv_dispi.inf_amd64_e92a0ac2e05fb2ca\
nvldumdx.dll: Certificate is not valid

(The jury is still out on whether it is Nvidia or Virtualbox at fault, or both.)

With 3D enabled on your guest video, this might cause reset or failure of the guest video.

See fth0's suggestions:
viewtopic.php?f=6&t=99059&p=480386#p480336

https://www.nvidia.com/en-us/geforce/fo ... mentPage=1

Your guest OS reports some kind of left-over Guest Additions that didn't fully clear when you installed 6.1.12's GAs:

00:00:22.551282 VMMDev: Guest Additions information report: Version 6.1.12 r139181 '6.1.12'
00:00:26.466435 VMMDev: Guest Log: VBoxService 5.2.42_Ubuntu r137960 (verbosity: 0) linux.amd64 (Jun 5 2020 08:26:08) release log

I have no idea how to fix this.

I don't know if these next points might influence the problem or are just oddities.

You're apparently running an Ubuntu guest in a Arch Linux environment:

00:00:02.574620 Guest OS type: 'ArchLinux_64'
00:00:02.578374 File system of 'C:\Users\Administrator\VirtualBox VMs\Ubuntu\Snapshots' (snapshots) is ntfs
00:00:02.578382 File system of 'C:\Users\Administrator\VirtualBox VMs\Ubuntu\Ubuntu.vdi' is ntfs

You have all four base host cores available for the guest to use:

00:00:02.595495 NumCPUs <integer> = 0x0000000000000004 (4)
00:00:03.250259 CPUM: Physical host cores: 4

More cores slows down a guest, due to extra scheduling oversight on the host. Additionally, if the guest goes full-throttle on all four cores, the host can go unstable. Hyperthreads do not count for running a Virtualbox guest.