Black screen after upgrading to Ubuntu 20

[dmitryb4]

Hello.
HostOS - Windows 10
VirtualBox - Version 6.1.38 r153438 (Qt5.6.2)
Guest system - Ubuntu 18.04 (Upgraded to 20.1).
Some time ago, Ubuntu reported that it might upgrade to version 20.1. I performed the upgrade. At the end, Ubuntu offered to reboot. After the reboot, it began to show a black screen.
First, the boot logo at the bottom, then a black screen.
This can be seen on the video.
h t t p s: // disk. yandex. ru/i/N2QFXWVfL92z-Q
(Sorry I can't post links yet.)

Can you tell me if there is a problem in VirtualBox and how to treat it?

[scottgus1]

Ubuntu is known to go blackscreen if there is not enough free disk space to start the desktop environment. This happens in real PCs too. The solution is to log on text-only and delete stuff until the desktop environment can start. Web-search how to fix this in an Ubuntu PC and apply the steps to the VM. Also see How to Resize a Drive

[dmitryb4]

If you look at setting up a virtual machine, then there is enough disk space.

[dmitryb4]

I used instruction to restart ubuntu in Recovery-mode
h t t p s :// linuxhint . com / boot-ubuntu-into-recovery-mode/#:~:text=You%20can%20get%20recovery%20mode,network%2C%20grub%2C%20and%20root.
and upgraded system to version 22.04
but that doesn't help much.

Now the system boots but the mouse does not work correctly. Some parts of the screen are not pressed.
The system can only be operated in Recovery-mode.
Installing VirtualBox Guest Additions does not help.