Cannot open Virtual Box 6.0 after an interrupted update

Question

I accidentally interrupted the Virtual Box 6.0 update that was installed and working correctly on my Ubuntu 18.04. After that, Virtual Box does not open. Running virtualbox through the terminal throws multiple **Qt WARNING: QString::arg: Argument Missing: and finally does not open the application. I try to completely uninstall VirtualBox with: sudo apt-get remove --purge '^virtual*'. But when I redownload and install Virtual Box 6.0 the same error occurs.

**My terminal is not in English, this is an approximate translation of the error messages thrown:

Qt ATTENTION: QString :: arg: argument missing: upgrade virtual machine registration (% 1),
Qt ATTENTION: QString :: arg: Missing argument: Open host network owner (% 1) only,
Qt ATTENTION: QString :: arg: missing argument: update networks across the host (% 1),
Qt ATTENTION: QString :: arg: argument missing: update registry of virtual machine (% 1), Ctrl + Shift + R
Qt ATTENTION: QString :: arg: argument missing: Open host network owners (% 1), Ctrl + Shift + P
Qt WARNING: QString :: arg: argument missing: update host-only networks (% 1), Ctrl + Shift + F
Qt ATTENTION: QString :: arg: argument missing: upgrade virtual machine registration (% 1),
Qt ATTENTION: QString :: arg: argument missing: upgrade virtual machine registration (% 1),
Qt ATTENTION: QString :: arg: argument missing: upgrade virtual machine registration (% 1),
Qt ATTENTION: QString :: arg: argument missing: update registry of virtual machine (% 1), Ctrl + Shift + R
Qt ATTENTION: QString :: arg: argument missing: Open host network owners (% 1), Ctrl + Shift + P
Qt WARNING: QString :: arg: argument missing: update host-only networks (% 1), Ctrl + Shift + F
Qt ATTENTION: QString :: arg: argument missing: upgrade virtual machine registration (% 1),
Qt ATTENTION: QString :: arg: argument missing: upgrade virtual machine registration (% 1),
Qt ATTENTION: QString :: arg: argument missing: upgrade virtual machine registration (% 1),
Gdk-Message: 15: 59: 01.783: VirtualBox: Error IO 0 fatal (Success) to the X server: 0.

Help, please, I can't fix it. Thank you

Answer 1

Partially solved!

In this post Virtualbox 6.0, crashes immediately on ubuntu 18.10 they found what the problem is. Apparently, this failure to start Virtual Box occurs when the laptop is connected via HDMI to a second monitor. So, doesn't use a second monitor solves the problem, Virtual Box starts with no problem then. Now we should find a solution to allow to work with Virtual Box having two monitors connected...