With a help of great @FedonKadifeli I was able to solve the issue.
First and foremost - the guest OS is Ubuntu 20.04 LTS Server.
From a running guest OS window install Guest Additions. Go to :
Devices - > Insert Guest Additions CD Image
Then to the guest OS command line :
sudo apt update
sudo apt upgrade
sudo mount /dev/sr0 /cdrom
mount: /cdrom: WARNING: device write-protected, mounted read-only. # This is OK
cd /cdrom
sudo bash ./VBoxLinuxAdditions.run
The output of the last command should be something like that :
However, the last 3 lines of the output I got was saying this :
"This system is currently not set up to build kernel modules.
Please install the gcc make perl packages from your distribution.
VirtualBox Guest Additions: Running kernel modules will not be replaced until
the system is restarted"
So, first I had to install additional packages. And anything extra that may be needed:
sudo apt install gcc
sudo apt install make
sudo apt install perl
Restart the guest :
reboot
Then from a Guest OS window go to :
Devices - Shared Folders - Shared Folders Settings - Add new Shared Folder :
Folder Path : C:\Users\as_to\Desktop\foo
Folder Name : foo
Mount point : /home/tomas/bar - This will create a directory after you close this window
Auto-mount (check)
Make Permanent (check)
Press OK to close the window.
Next, if you try to cd into bar you will get permission denied :
cd bar/
-bash: cd: bar/: Permission denied
Add user to the group "vboxsf" and logout/login again for the changes to be applied:
sudo usermod -aG vboxsf tomas
logout
And that's it. All should work now.
Thank you again @FedonKadifeli, awesome guy.
