virtualbox.org

Currently using VirtualBox 6.1.32. Host runs Windows 10, and VM is using Ubuntu 20.04.4. Both systems are x64. The VM system has 4096 MB base memory and 128 MB for video memory.

Initially, I was using previous versions of both VirtualBox and Ubuntu, but was able to start up the VM with no problems. Although, after using it for a few minutes I started having problems with being unable to open applications and decided to restart the VM. After restarting it, the VM would get stuck on a black screen with a still white underscore. After going through and updating both VirtualBox and Ubuntu, I'm still stuck on the black screen.

*I did revert to the previous version of VirtualBox and Ubuntu that I used, but the problem was still there.

*I have also created a new VM and did a fresh install of Ubuntu and it was able to start up. It seems that the problem is only on one VM.

Doesn't look like anything wrong in the VM's 'hardware'. The Guest Additions start up, which means the VM's OS is running.

LH-65 wrote:I have also created a new VM and did a fresh install of Ubuntu and it was able to start up.

Also a very good troubleshooting step, thumbs up!

I'm going to guess this is a problem inside the VM OS. 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.

You were right, I freed up some space and was able to start up. Thank you!

I had gone through with autoclean and autoremove. But I had to directly remove unused applications and increase the allocated memory size a little bit for the update to go through.

Great! Glad you're up and running.

See How to Resize a Drive to make the VM's drive bigger.